From 44ad2306afb4cddda2c0af1593eceae1a13b96b4 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Sun, 19 Sep 2021 06:56:48 +0500
Subject: [PATCH 01/15] feat(lambda-nodejs) experimental decorators support

---
 packages/@aws-cdk/aws-lambda-nodejs/README.md | 18 +++++++++
 .../@aws-cdk/aws-lambda-nodejs/lib/Dockerfile |  3 ++
 .../aws-lambda-nodejs/lib/bundling.ts         | 36 +++++++++++++++--
 .../@aws-cdk/aws-lambda-nodejs/lib/types.ts   | 10 +++++
 .../@aws-cdk/aws-lambda-nodejs/lib/util.ts    | 17 ++++++++
 .../aws-lambda-nodejs/test/bundling.test.ts   | 40 +++++++++++++++++++
 .../aws-lambda-nodejs/test/util.test.ts       | 10 ++++-
 7 files changed, 130 insertions(+), 4 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/README.md b/packages/@aws-cdk/aws-lambda-nodejs/README.md
index 22347b28b1dd9..15b2ade10d8dd 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/README.md
+++ b/packages/@aws-cdk/aws-lambda-nodejs/README.md
@@ -224,6 +224,24 @@ an array of commands to run. Commands are chained with `&&`.
 The commands will run in the environment in which bundling occurs: inside the
 container for Docker bundling or on the host OS for local bundling.
 
+## Pre Compilation with TSC
+
+It is possible to run compilation using typescript compiler before bundling, 
+this is for adding support of `emitDecoratorMetadata` which `esbuild` doesn't support it natively.
+see <https://github.com/aws/aws-cdk/issues/13767>.
+
+```ts
+new lambda.NodejsFunction(this, 'my-handler', {
+  bundling: {
+    preCompilation: true,
+    tsconfig: 'tsconfig.json'
+  },
+});
+```
+
+`tsconfig` is required to enable `preCompilation` as `tsc` will use your `tsconfig` for transpilation. 
+Output of the transpilation will be found under `cdk.out/tsc-compile`
+
 ## Customizing Docker bundling
 
 Use `bundling.environment` to define environments variables when `esbuild` runs:
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/Dockerfile b/packages/@aws-cdk/aws-lambda-nodejs/lib/Dockerfile
index 578b1b8135d5c..54969bb5fde2c 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/Dockerfile
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/Dockerfile
@@ -9,6 +9,9 @@ RUN npm install --global yarn@1.22.5
 # Install pnpm
 RUN npm install --global pnpm
 
+# Install typescript
+RUN npm install --global typescript
+
 # Install esbuild
 # (unsafe-perm because esbuild has a postinstall script)
 ARG ESBUILD_VERSION=0
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index 3c33ad74f2471..37975d496aa40 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -5,9 +5,10 @@ import * as cdk from '@aws-cdk/core';
 import { EsbuildInstallation } from './esbuild-installation';
 import { PackageManager } from './package-manager';
 import { BundlingOptions, SourceMapMode } from './types';
-import { exec, extractDependencies, findUp } from './util';
+import { exec, extractDependencies, extractRootDir, findUp } from './util';
 
 const ESBUILD_MAJOR_VERSION = '0';
+const PRE_COMPILATION_DIR = 'cdk.out/tsc-compile';
 
 /**
  * Bundling properties
@@ -32,6 +33,12 @@ export interface BundlingProps extends BundlingOptions {
    * Path to project root
    */
   readonly projectRoot: string;
+
+  /**
+   * Force pre-transpilation using TSC before bundling
+   */
+  readonly preCompilation?: boolean
+
 }
 
 /**
@@ -67,6 +74,7 @@ export class Bundling implements cdk.BundlingOptions {
   private readonly relativeDepsLockFilePath: string;
   private readonly externals: string[];
   private readonly packageManager: PackageManager;
+  private readonly preCompilation?: boolean;
 
   constructor(private readonly props: BundlingProps) {
     this.packageManager = PackageManager.fromLockFile(props.depsLockFilePath);
@@ -85,6 +93,10 @@ export class Bundling implements cdk.BundlingOptions {
       this.relativeTsconfigPath = path.relative(this.projectRoot, path.resolve(props.tsconfig));
     }
 
+    if (props.preCompilation && (/\.(tsx?)$/.test(props.entry))) {
+      this.preCompilation = true;
+    }
+
     this.externals = [
       ...props.externalModules ?? ['aws-sdk'], // Mark aws-sdk as external by default (available in the runtime)
       ...props.nodeModules ?? [], // Mark the modules that we are going to install as externals also
@@ -122,6 +134,23 @@ export class Bundling implements cdk.BundlingOptions {
 
   private createBundlingCommand(options: BundlingCommandOptions): string {
     const pathJoin = osPathJoin(options.osPlatform);
+    const npx = options.osPlatform === 'win32' ? 'npx.cmd' : 'npx';
+
+    let compileCommand = '';
+    let relativeJsEntryPath;
+
+    if (this.preCompilation) {
+      relativeJsEntryPath = pathJoin(options.inputDir, PRE_COMPILATION_DIR, this.relativeEntryPath)
+        .replace(/\.(tsx)$/, '.jsx').replace(/\.(ts)$/, '.js');
+
+      if (this.relativeTsconfigPath) {
+        const tsconfigPath = pathJoin(options.inputDir, this.relativeTsconfigPath);
+        const rootDir = extractRootDir(tsconfigPath);
+        compileCommand =`${npx} tsc --project ${tsconfigPath} --outDir ${pathJoin(options.inputDir, PRE_COMPILATION_DIR, rootDir ?? '')}`;
+      } else {
+        throw new Error('preCompilation cannot be used when tsconfig is undefined');
+      }
+    }
 
     const loaders = Object.entries(this.props.loader ?? {});
     const defines = Object.entries(this.props.define ?? {});
@@ -129,14 +158,14 @@ export class Bundling implements cdk.BundlingOptions {
     if (this.props.sourceMap === false && this.props.sourceMapMode) {
       throw new Error('sourceMapMode cannot be used when sourceMap is false');
     }
-    // eslint-disable-next-line no-console
+
     const sourceMapEnabled = this.props.sourceMapMode ?? this.props.sourceMap;
     const sourceMapMode = this.props.sourceMapMode ?? SourceMapMode.DEFAULT;
     const sourceMapValue = sourceMapMode === SourceMapMode.DEFAULT ? '' : `=${this.props.sourceMapMode}`;
 
     const esbuildCommand: string[] = [
       options.esbuildRunner,
-      '--bundle', `"${pathJoin(options.inputDir, this.relativeEntryPath)}"`,
+      '--bundle', `"${relativeJsEntryPath ? relativeJsEntryPath : pathJoin(options.inputDir, this.relativeEntryPath)}"`,
       `--target=${this.props.target ?? toTarget(this.props.runtime)}`,
       '--platform=node',
       `--outfile="${pathJoin(options.outputDir, 'index.js')}"`,
@@ -178,6 +207,7 @@ export class Bundling implements cdk.BundlingOptions {
     }
 
     return chain([
+      compileCommand,
       ...this.props.commandHooks?.beforeBundling(options.inputDir, options.outputDir) ?? [],
       esbuildCommand.join(' '),
       ...(this.props.nodeModules && this.props.commandHooks?.beforeInstall(options.inputDir, options.outputDir)) ?? [],
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
index 8d0d263fe64e6..f68559b404a5c 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
@@ -197,6 +197,16 @@ export interface BundlingOptions {
    */
   readonly forceDockerBundling?: boolean;
 
+  /**
+  * Force pre-transpilation using TSC before running file through bundling step.
+  * This usually is not required unless you are using new experimental features that
+  * are only supported by typescript's`tsc` compiler.
+  * One example of such feature is `experimentalDecorators`.
+  *
+  * @default false
+  */
+  readonly preCompilation?: boolean
+
   /**
    * A custom bundling Docker image.
    *
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
index 5ead91793e93b..8866b828dd7e5 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
@@ -110,3 +110,20 @@ export function extractDependencies(pkgPath: string, modules: string[]): { [key:
 
   return dependencies;
 }
+
+/**
+ * Extract rootDir from tsConfig.
+ */
+export function extractRootDir(tsconfigPath: string): string | undefined {
+  try {
+    // eslint-disable-next-line @typescript-eslint/no-require-imports
+    const { extends: extendedConfig, compilerOptions: { rootDir = undefined } = {} } = require(tsconfigPath);
+    if (!rootDir && extendedConfig) {
+      return extractRootDir(path.resolve(tsconfigPath.replace(/[^\/]+$/, ''), extendedConfig));
+    }
+    return rootDir;
+
+  } catch (err) {
+    return;
+  }
+}
\ No newline at end of file
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index a38a6fa08d5bc..653891488756f 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -218,6 +218,46 @@ test('esbuild bundling with esbuild options', () => {
   expect(bundleProcess.stdout.toString()).toMatchSnapshot();
 });
 
+test('esbuild bundling with pre-compilations', () => {
+  Bundling.bundle({
+    entry,
+    projectRoot,
+    depsLockFilePath,
+    runtime: Runtime.NODEJS_14_X,
+    forceDockerBundling: true,
+    tsconfig,
+    preCompilation: true,
+  });
+
+  // Correctly bundles with esbuild
+  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
+    assetHashType: AssetHashType.OUTPUT,
+    bundling: expect.objectContaining({
+      command: [
+        'bash', '-c',
+        [
+          'npx tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/cdk.out/tsc-compile &&',
+          'esbuild --bundle \"/asset-input/cdk.out/tsc-compile/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
+          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
+        ].join(' '),
+      ],
+    }),
+  });
+});
+
+test('esbuild bundling with pre-compilations without tsconfig', () => {
+  expect(() => {
+    Bundling.bundle({
+      entry,
+      projectRoot,
+      depsLockFilePath,
+      runtime: Runtime.NODEJS_14_X,
+      forceDockerBundling: true,
+      preCompilation: true,
+    });
+  }).toThrow('preCompilation cannot be used when tsconfig is undefined');
+});
+
 test('esbuild bundling source map default', () => {
   Bundling.bundle({
     entry,
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
index 4962ed203b31f..b1bf269a2766a 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
@@ -1,6 +1,6 @@
 import * as child_process from 'child_process';
 import * as path from 'path';
-import { callsites, exec, extractDependencies, findUp } from '../lib/util';
+import { callsites, exec, extractDependencies, extractRootDir, findUp } from '../lib/util';
 
 beforeEach(() => {
   jest.clearAllMocks();
@@ -120,3 +120,11 @@ describe('extractDependencies', () => {
     )).toThrow(/Cannot extract version for module 'unknown'/);
   });
 });
+
+describe('extractRootDir', () => {
+  test('with rootDir defined in tsconfig.json', () => {
+    expect(extractRootDir(
+      path.join(__dirname, '../tsconfig.json'),
+    )).toEqual(undefined);
+  });
+});

From a4e0db80b0546caddf31f555bb3f5ea211423d55 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Sun, 3 Oct 2021 05:15:00 +0500
Subject: [PATCH 02/15] PR feedback

---
 .../aws-lambda-nodejs/lib/bundling.ts         | 59 +++++++++++--------
 ...nstallation.ts => package-installation.ts} | 10 ++--
 .../@aws-cdk/aws-lambda-nodejs/lib/types.ts   |  4 +-
 .../aws-lambda-nodejs/test/bundling.test.ts   | 19 +++---
 4 files changed, 52 insertions(+), 40 deletions(-)
 rename packages/@aws-cdk/aws-lambda-nodejs/lib/{esbuild-installation.ts => package-installation.ts} (71%)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index 37975d496aa40..1ddb26598ee2e 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -2,7 +2,7 @@ import * as os from 'os';
 import * as path from 'path';
 import { AssetCode, Code, Runtime } from '@aws-cdk/aws-lambda';
 import * as cdk from '@aws-cdk/core';
-import { EsbuildInstallation } from './esbuild-installation';
+import { PackageInstallation } from './package-installation';
 import { PackageManager } from './package-manager';
 import { BundlingOptions, SourceMapMode } from './types';
 import { exec, extractDependencies, extractRootDir, findUp } from './util';
@@ -59,7 +59,12 @@ export class Bundling implements cdk.BundlingOptions {
     this.esbuildInstallation = undefined;
   }
 
-  private static esbuildInstallation?: EsbuildInstallation;
+  public static clearTscInstallationCache(): void {
+    this.tscInstallation = undefined;
+  }
+
+  private static esbuildInstallation?: PackageInstallation;
+  private static tscInstallation?: PackageInstallation;
 
   // Core bundling options
   public readonly image: cdk.DockerImage;
@@ -74,12 +79,12 @@ export class Bundling implements cdk.BundlingOptions {
   private readonly relativeDepsLockFilePath: string;
   private readonly externals: string[];
   private readonly packageManager: PackageManager;
-  private readonly preCompilation?: boolean;
 
   constructor(private readonly props: BundlingProps) {
     this.packageManager = PackageManager.fromLockFile(props.depsLockFilePath);
 
-    Bundling.esbuildInstallation = Bundling.esbuildInstallation ?? EsbuildInstallation.detect();
+    Bundling.esbuildInstallation = Bundling.esbuildInstallation ?? PackageInstallation.detect('esbuild');
+    Bundling.tscInstallation = Bundling.tscInstallation ?? PackageInstallation.detect('tsc');
 
     this.projectRoot = props.projectRoot;
     this.relativeEntryPath = path.relative(this.projectRoot, path.resolve(props.entry));
@@ -93,8 +98,8 @@ export class Bundling implements cdk.BundlingOptions {
       this.relativeTsconfigPath = path.relative(this.projectRoot, path.resolve(props.tsconfig));
     }
 
-    if (props.preCompilation && (/\.(tsx?)$/.test(props.entry))) {
-      this.preCompilation = true;
+    if (props.preCompilation && !/\.tsx?$/.test(props.entry)) {
+      throw new Error('preCompilation can only be used with typescript files');
     }
 
     this.externals = [
@@ -104,8 +109,8 @@ export class Bundling implements cdk.BundlingOptions {
 
     // Docker bundling
     const shouldBuildImage = props.forceDockerBundling || !Bundling.esbuildInstallation;
-    this.image = shouldBuildImage
-      ? props.dockerImage ?? cdk.DockerImage.fromBuild(path.join(__dirname, '../lib'), {
+    this.image = shouldBuildImage ? props.dockerImage ?? cdk.DockerImage.fromBuild(path.join(__dirname, '../lib'),
+      {
         buildArgs: {
           ...props.buildArgs ?? {},
           IMAGE: props.runtime.bundlingImage.image,
@@ -118,6 +123,7 @@ export class Bundling implements cdk.BundlingOptions {
       inputDir: cdk.AssetStaging.BUNDLING_INPUT_DIR,
       outputDir: cdk.AssetStaging.BUNDLING_OUTPUT_DIR,
       esbuildRunner: 'esbuild', // esbuild is installed globally in the docker image
+      tscRunner: 'tsc', // tsc is installed globally in the docker image
       osPlatform: 'linux', // linux docker image
     });
     this.command = ['bash', '-c', bundlingCommand];
@@ -134,24 +140,23 @@ export class Bundling implements cdk.BundlingOptions {
 
   private createBundlingCommand(options: BundlingCommandOptions): string {
     const pathJoin = osPathJoin(options.osPlatform);
-    const npx = options.osPlatform === 'win32' ? 'npx.cmd' : 'npx';
 
-    let compileCommand = '';
-    let relativeJsEntryPath;
+    let tscCommand = '';
+    let relativeEntryPath = this.relativeEntryPath;
 
-    if (this.preCompilation) {
-      relativeJsEntryPath = pathJoin(options.inputDir, PRE_COMPILATION_DIR, this.relativeEntryPath)
-        .replace(/\.(tsx)$/, '.jsx').replace(/\.(ts)$/, '.js');
-
-      if (this.relativeTsconfigPath) {
-        const tsconfigPath = pathJoin(options.inputDir, this.relativeTsconfigPath);
-        const rootDir = extractRootDir(tsconfigPath);
-        compileCommand =`${npx} tsc --project ${tsconfigPath} --outDir ${pathJoin(options.inputDir, PRE_COMPILATION_DIR, rootDir ?? '')}`;
-      } else {
+    if (this.props.preCompilation) {
+      if (!this.relativeTsconfigPath) {
         throw new Error('preCompilation cannot be used when tsconfig is undefined');
       }
+      relativeEntryPath = pathJoin(PRE_COMPILATION_DIR, relativeEntryPath).replace(/\.ts(x?)$/, '.js$1');
+
+      const tsconfigPath = pathJoin(options.inputDir, this.relativeTsconfigPath);
+      const rootDir = extractRootDir(tsconfigPath);
+      process.stderr.write(`Compiling your project using typescript compiler version: ${Bundling.tscInstallation?.version} \n`);
+      tscCommand =`${options.tscRunner} --project ${tsconfigPath} --outDir ${pathJoin(options.inputDir, PRE_COMPILATION_DIR, rootDir ?? '')}`;
     }
 
+
     const loaders = Object.entries(this.props.loader ?? {});
     const defines = Object.entries(this.props.define ?? {});
 
@@ -165,7 +170,7 @@ export class Bundling implements cdk.BundlingOptions {
 
     const esbuildCommand: string[] = [
       options.esbuildRunner,
-      '--bundle', `"${relativeJsEntryPath ? relativeJsEntryPath : pathJoin(options.inputDir, this.relativeEntryPath)}"`,
+      '--bundle', `"${pathJoin(options.inputDir, relativeEntryPath)}"`,
       `--target=${this.props.target ?? toTarget(this.props.runtime)}`,
       '--platform=node',
       `--outfile="${pathJoin(options.outputDir, 'index.js')}"`,
@@ -207,8 +212,8 @@ export class Bundling implements cdk.BundlingOptions {
     }
 
     return chain([
-      compileCommand,
       ...this.props.commandHooks?.beforeBundling(options.inputDir, options.outputDir) ?? [],
+      tscCommand,
       esbuildCommand.join(' '),
       ...(this.props.nodeModules && this.props.commandHooks?.beforeInstall(options.inputDir, options.outputDir)) ?? [],
       depsCommand,
@@ -218,10 +223,11 @@ export class Bundling implements cdk.BundlingOptions {
 
   private getLocalBundlingProvider(): cdk.ILocalBundling {
     const osPlatform = os.platform();
-    const createLocalCommand = (outputDir: string, esbuild: EsbuildInstallation) => this.createBundlingCommand({
+    const createLocalCommand = (outputDir: string, esbuild: PackageInstallation, tsc: PackageInstallation) => this.createBundlingCommand({
       inputDir: this.projectRoot,
       outputDir,
       esbuildRunner: esbuild.isLocal ? this.packageManager.runBinCommand('esbuild') : 'esbuild',
+      tscRunner: tsc.isLocal ? this.packageManager.runBinCommand('tsc') : 'tsc',
       osPlatform,
     });
     const environment = this.props.environment ?? {};
@@ -238,7 +244,11 @@ export class Bundling implements cdk.BundlingOptions {
           throw new Error(`Expected esbuild version ${ESBUILD_MAJOR_VERSION}.x but got ${Bundling.esbuildInstallation.version}`);
         }
 
-        const localCommand = createLocalCommand(outputDir, Bundling.esbuildInstallation);
+        if (!Bundling.tscInstallation) {
+          throw new Error('Unable to find typescript locally or globally make sure install typescript in you dependencies');
+        }
+
+        const localCommand = createLocalCommand(outputDir, Bundling.esbuildInstallation, Bundling.tscInstallation);
 
         exec(
           osPlatform === 'win32' ? 'cmd' : 'bash',
@@ -267,6 +277,7 @@ interface BundlingCommandOptions {
   readonly inputDir: string;
   readonly outputDir: string;
   readonly esbuildRunner: string;
+  readonly tscRunner: string;
   readonly osPlatform: NodeJS.Platform;
 }
 
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/esbuild-installation.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/package-installation.ts
similarity index 71%
rename from packages/@aws-cdk/aws-lambda-nodejs/lib/esbuild-installation.ts
rename to packages/@aws-cdk/aws-lambda-nodejs/lib/package-installation.ts
index 8ef2e8dbb23d9..af9b1f50fdebf 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/esbuild-installation.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/package-installation.ts
@@ -2,13 +2,13 @@ import { spawnSync } from 'child_process';
 import { tryGetModuleVersion } from './util';
 
 /**
- * An esbuild installation
+ * Package installation
  */
-export abstract class EsbuildInstallation {
-  public static detect(): EsbuildInstallation | undefined {
+export abstract class PackageInstallation {
+  public static detect(module: string): PackageInstallation | undefined {
     try {
       // Check local version first
-      const version = tryGetModuleVersion('esbuild');
+      const version = tryGetModuleVersion(module);
       if (version) {
         return {
           isLocal: true,
@@ -17,7 +17,7 @@ export abstract class EsbuildInstallation {
       }
 
       // Fallback to a global version
-      const esbuild = spawnSync('esbuild', ['--version']);
+      const esbuild = spawnSync(module, ['--version']);
       if (esbuild.status === 0 && !esbuild.error) {
         return {
           isLocal: false,
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
index f68559b404a5c..d217601fcd4b2 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
@@ -200,8 +200,8 @@ export interface BundlingOptions {
   /**
   * Force pre-transpilation using TSC before running file through bundling step.
   * This usually is not required unless you are using new experimental features that
-  * are only supported by typescript's`tsc` compiler.
-  * One example of such feature is `experimentalDecorators`.
+  * are only supported by typescript's `tsc` compiler.
+  * One example of such feature is `emitDecoratorMetadata`.
   *
   * @default false
   */
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index 653891488756f..f7d99df231a7a 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -5,7 +5,7 @@ import { Code, Runtime } from '@aws-cdk/aws-lambda';
 import { AssetHashType, DockerImage } from '@aws-cdk/core';
 import { version as delayVersion } from 'delay/package.json';
 import { Bundling } from '../lib/bundling';
-import { EsbuildInstallation } from '../lib/esbuild-installation';
+import { PackageInstallation } from '../lib/package-installation';
 import { LogLevel, SourceMapMode } from '../lib/types';
 import * as util from '../lib/util';
 
@@ -13,17 +13,13 @@ jest.mock('@aws-cdk/aws-lambda');
 
 // Mock DockerImage.fromAsset() to avoid building the image
 let fromBuildMock: jest.SpyInstance<DockerImage>;
-let detectEsbuildMock: jest.SpyInstance<EsbuildInstallation | undefined>;
+let detectPackageInstallationMock: jest.SpyInstance<PackageInstallation | undefined>;
 beforeEach(() => {
   jest.clearAllMocks();
   jest.resetAllMocks();
   jest.restoreAllMocks();
   Bundling.clearEsbuildInstallationCache();
-
-  detectEsbuildMock = jest.spyOn(EsbuildInstallation, 'detect').mockReturnValue({
-    isLocal: true,
-    version: '0.8.8',
-  });
+  Bundling.clearTscInstallationCache();
 
   fromBuildMock = jest.spyOn(DockerImage, 'fromBuild').mockReturnValue({
     image: 'built-image',
@@ -31,6 +27,11 @@ beforeEach(() => {
     run: () => {},
     toJSON: () => 'built-image',
   });
+
+  detectPackageInstallationMock = jest.spyOn(PackageInstallation, 'detect').mockReturnValue({
+    isLocal: true,
+    version: '0.8.8',
+  });
 });
 
 let projectRoot = '/project';
@@ -236,7 +237,7 @@ test('esbuild bundling with pre-compilations', () => {
       command: [
         'bash', '-c',
         [
-          'npx tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/cdk.out/tsc-compile &&',
+          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/cdk.out/tsc-compile &&',
           'esbuild --bundle \"/asset-input/cdk.out/tsc-compile/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
           '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
         ].join(' '),
@@ -450,7 +451,7 @@ test('Local bundling', () => {
 
 
 test('Incorrect esbuild version', () => {
-  detectEsbuildMock.mockReturnValueOnce({
+  detectPackageInstallationMock.mockReturnValueOnce({
     isLocal: true,
     version: '3.4.5',
   });

From 3fed2171bac707de4faadcc94077305f410bfec5 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Sun, 3 Oct 2021 05:36:26 +0500
Subject: [PATCH 03/15] fix tests

---
 ...-installation.test.ts => package-installation.test.ts} | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
 rename packages/@aws-cdk/aws-lambda-nodejs/test/{esbuild-installation.test.ts => package-installation.test.ts} (84%)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/esbuild-installation.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/package-installation.test.ts
similarity index 84%
rename from packages/@aws-cdk/aws-lambda-nodejs/test/esbuild-installation.test.ts
rename to packages/@aws-cdk/aws-lambda-nodejs/test/package-installation.test.ts
index 24b9b512c98bc..e7afddc09fdbb 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/esbuild-installation.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/package-installation.test.ts
@@ -1,12 +1,12 @@
 import * as child_process from 'child_process';
-import { EsbuildInstallation } from '../lib/esbuild-installation';
+import { PackageInstallation } from '../lib/package-installation';
 import * as util from '../lib/util';
 
 // eslint-disable-next-line @typescript-eslint/no-require-imports, import/no-extraneous-dependencies
 const version = require('esbuild/package.json').version;
 
 test('detects local version', () => {
-  expect(EsbuildInstallation.detect()).toEqual({
+  expect(PackageInstallation.detect('esbuild')).toEqual({
     isLocal: true,
     version,
   });
@@ -23,7 +23,7 @@ test('checks global version if local detection fails', () => {
     signal: null,
   });
 
-  expect(EsbuildInstallation.detect()).toEqual({
+  expect(PackageInstallation.detect('esbuild')).toEqual({
     isLocal: false,
     version: 'global-version',
   });
@@ -44,7 +44,7 @@ test('returns undefined on error', () => {
     signal: null,
   });
 
-  expect(EsbuildInstallation.detect()).toBeUndefined();
+  expect(PackageInstallation.detect('esbuild')).toBeUndefined();
 
   spawnSyncMock.mockRestore();
   getModuleVersionMock.mockRestore();

From 4780f611f036f42c22c4b80ec8fb71905736dc72 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Tue, 5 Oct 2021 15:04:36 +0500
Subject: [PATCH 04/15] PR feedback

---
 .../aws-lambda-nodejs/lib/bundling.ts         | 24 ++++++++++---------
 .../lib/package-installation.ts               |  6 ++---
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index 1ddb26598ee2e..3288837a98e17 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -65,6 +65,7 @@ export class Bundling implements cdk.BundlingOptions {
 
   private static esbuildInstallation?: PackageInstallation;
   private static tscInstallation?: PackageInstallation;
+  private static tscCompiled = false
 
   // Core bundling options
   public readonly image: cdk.DockerImage;
@@ -148,12 +149,17 @@ export class Bundling implements cdk.BundlingOptions {
       if (!this.relativeTsconfigPath) {
         throw new Error('preCompilation cannot be used when tsconfig is undefined');
       }
+
       relativeEntryPath = pathJoin(PRE_COMPILATION_DIR, relativeEntryPath).replace(/\.ts(x?)$/, '.js$1');
 
-      const tsconfigPath = pathJoin(options.inputDir, this.relativeTsconfigPath);
-      const rootDir = extractRootDir(tsconfigPath);
-      process.stderr.write(`Compiling your project using typescript compiler version: ${Bundling.tscInstallation?.version} \n`);
-      tscCommand =`${options.tscRunner} --project ${tsconfigPath} --outDir ${pathJoin(options.inputDir, PRE_COMPILATION_DIR, rootDir ?? '')}`;
+      if (!Bundling.tscCompiled) {
+        const tsconfigPath = pathJoin(options.inputDir, this.relativeTsconfigPath);
+        const rootDir = extractRootDir(tsconfigPath);
+        process.stderr.write(`Compiling your project using typescript compiler version: ${Bundling.tscInstallation?.version} \n`);
+        tscCommand = `${options.tscRunner} --project ${tsconfigPath} --outDir ${pathJoin(options.inputDir, PRE_COMPILATION_DIR, rootDir ?? '')}`;
+        // Setting this to avoid running tsc on every function
+        Bundling.tscCompiled = true;
+      }
     }
 
 
@@ -223,11 +229,11 @@ export class Bundling implements cdk.BundlingOptions {
 
   private getLocalBundlingProvider(): cdk.ILocalBundling {
     const osPlatform = os.platform();
-    const createLocalCommand = (outputDir: string, esbuild: PackageInstallation, tsc: PackageInstallation) => this.createBundlingCommand({
+    const createLocalCommand = (outputDir: string, esbuild: PackageInstallation, tsc?: PackageInstallation) => this.createBundlingCommand({
       inputDir: this.projectRoot,
       outputDir,
       esbuildRunner: esbuild.isLocal ? this.packageManager.runBinCommand('esbuild') : 'esbuild',
-      tscRunner: tsc.isLocal ? this.packageManager.runBinCommand('tsc') : 'tsc',
+      tscRunner: tsc && (tsc.isLocal ? this.packageManager.runBinCommand('tsc') : 'tsc'),
       osPlatform,
     });
     const environment = this.props.environment ?? {};
@@ -244,10 +250,6 @@ export class Bundling implements cdk.BundlingOptions {
           throw new Error(`Expected esbuild version ${ESBUILD_MAJOR_VERSION}.x but got ${Bundling.esbuildInstallation.version}`);
         }
 
-        if (!Bundling.tscInstallation) {
-          throw new Error('Unable to find typescript locally or globally make sure install typescript in you dependencies');
-        }
-
         const localCommand = createLocalCommand(outputDir, Bundling.esbuildInstallation, Bundling.tscInstallation);
 
         exec(
@@ -277,7 +279,7 @@ interface BundlingCommandOptions {
   readonly inputDir: string;
   readonly outputDir: string;
   readonly esbuildRunner: string;
-  readonly tscRunner: string;
+  readonly tscRunner?: string;
   readonly osPlatform: NodeJS.Platform;
 }
 
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/package-installation.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/package-installation.ts
index af9b1f50fdebf..789246badcceb 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/package-installation.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/package-installation.ts
@@ -17,11 +17,11 @@ export abstract class PackageInstallation {
       }
 
       // Fallback to a global version
-      const esbuild = spawnSync(module, ['--version']);
-      if (esbuild.status === 0 && !esbuild.error) {
+      const proc = spawnSync(module, ['--version']);
+      if (proc.status === 0 && !proc.error) {
         return {
           isLocal: false,
-          version: esbuild.stdout.toString().trim(),
+          version: proc.stdout.toString().trim(),
         };
       }
       return undefined;

From 46f291f95a89e1a8e157b53a7d33c4e17fa790ed Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Fri, 8 Oct 2021 05:17:21 +0500
Subject: [PATCH 05/15] PR Feedback

---
 .../aws-lambda-nodejs/lib/bundling.ts         |  33 +++--
 .../@aws-cdk/aws-lambda-nodejs/lib/util.ts    |  13 +-
 .../aws-lambda-nodejs/test/bundling.test.ts   | 130 ++++++++++++------
 .../aws-lambda-nodejs/test/util.test.ts       |  10 +-
 4 files changed, 120 insertions(+), 66 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index 3288837a98e17..422a91c01fba6 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -5,10 +5,9 @@ import * as cdk from '@aws-cdk/core';
 import { PackageInstallation } from './package-installation';
 import { PackageManager } from './package-manager';
 import { BundlingOptions, SourceMapMode } from './types';
-import { exec, extractDependencies, extractRootDir, findUp } from './util';
+import { exec, extractDependencies, extractCompilerOptions, findUp } from './util';
 
 const ESBUILD_MAJOR_VERSION = '0';
-const PRE_COMPILATION_DIR = 'cdk.out/tsc-compile';
 
 /**
  * Bundling properties
@@ -63,6 +62,10 @@ export class Bundling implements cdk.BundlingOptions {
     this.tscInstallation = undefined;
   }
 
+  public static clearTscCompilationCache(): void {
+    this.tscCompiled = false;
+  }
+
   private static esbuildInstallation?: PackageInstallation;
   private static tscInstallation?: PackageInstallation;
   private static tscCompiled = false
@@ -141,24 +144,24 @@ export class Bundling implements cdk.BundlingOptions {
 
   private createBundlingCommand(options: BundlingCommandOptions): string {
     const pathJoin = osPathJoin(options.osPlatform);
+    const tsconfig = pathJoin(options.inputDir, this.relativeTsconfigPath ?? 'tsconfig.json');
 
-    let tscCommand = '';
+    let tscCommand: string[] = [];
     let relativeEntryPath = this.relativeEntryPath;
 
     if (this.props.preCompilation) {
-      if (!this.relativeTsconfigPath) {
-        throw new Error('preCompilation cannot be used when tsconfig is undefined');
-      }
+      if (tsconfig) {
+        const { rootDir = '', outDir = '' } = extractCompilerOptions(tsconfig);
+        relativeEntryPath = pathJoin(outDir, relativeEntryPath).replace(/\.ts(x?)$/, '.js$1');
 
-      relativeEntryPath = pathJoin(PRE_COMPILATION_DIR, relativeEntryPath).replace(/\.ts(x?)$/, '.js$1');
+        if (!Bundling.tscCompiled) {
 
-      if (!Bundling.tscCompiled) {
-        const tsconfigPath = pathJoin(options.inputDir, this.relativeTsconfigPath);
-        const rootDir = extractRootDir(tsconfigPath);
-        process.stderr.write(`Compiling your project using typescript compiler version: ${Bundling.tscInstallation?.version} \n`);
-        tscCommand = `${options.tscRunner} --project ${tsconfigPath} --outDir ${pathJoin(options.inputDir, PRE_COMPILATION_DIR, rootDir ?? '')}`;
-        // Setting this to avoid running tsc on every function
-        Bundling.tscCompiled = true;
+          tscCommand = [
+            `${options.tscRunner} --project ${tsconfig}`,
+            ...outDir ? [`--outDir ${pathJoin(options.inputDir, outDir, rootDir)}`] : [],
+          ];
+          Bundling.tscCompiled = true;
+        }
       }
     }
 
@@ -219,7 +222,7 @@ export class Bundling implements cdk.BundlingOptions {
 
     return chain([
       ...this.props.commandHooks?.beforeBundling(options.inputDir, options.outputDir) ?? [],
-      tscCommand,
+      tscCommand.join(' '),
       esbuildCommand.join(' '),
       ...(this.props.nodeModules && this.props.commandHooks?.beforeInstall(options.inputDir, options.outputDir)) ?? [],
       depsCommand,
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
index 8866b828dd7e5..5717456608a56 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
@@ -112,16 +112,17 @@ export function extractDependencies(pkgPath: string, modules: string[]): { [key:
 }
 
 /**
- * Extract rootDir from tsConfig.
+ * Returns compilerOptions from tsconfig.json
  */
-export function extractRootDir(tsconfigPath: string): string | undefined {
+export function extractCompilerOptions(tsconfigPath: string, previous?: { [key: string]: string }): any | undefined {
   try {
     // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const { extends: extendedConfig, compilerOptions: { rootDir = undefined } = {} } = require(tsconfigPath);
-    if (!rootDir && extendedConfig) {
-      return extractRootDir(path.resolve(tsconfigPath.replace(/[^\/]+$/, ''), extendedConfig));
+    const { extends: extendedConfig, compilerOptions: current } = require(tsconfigPath);
+    const merged = { ...previous, ...current };
+    if (extendedConfig) {
+      return extractCompilerOptions(path.resolve(tsconfigPath.replace(/[^\/]+$/, ''), extendedConfig), merged);
     }
-    return rootDir;
+    return merged;
 
   } catch (err) {
     return;
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index f7d99df231a7a..2c0c6fdb42e3d 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -219,46 +219,6 @@ test('esbuild bundling with esbuild options', () => {
   expect(bundleProcess.stdout.toString()).toMatchSnapshot();
 });
 
-test('esbuild bundling with pre-compilations', () => {
-  Bundling.bundle({
-    entry,
-    projectRoot,
-    depsLockFilePath,
-    runtime: Runtime.NODEJS_14_X,
-    forceDockerBundling: true,
-    tsconfig,
-    preCompilation: true,
-  });
-
-  // Correctly bundles with esbuild
-  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
-    assetHashType: AssetHashType.OUTPUT,
-    bundling: expect.objectContaining({
-      command: [
-        'bash', '-c',
-        [
-          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/cdk.out/tsc-compile &&',
-          'esbuild --bundle \"/asset-input/cdk.out/tsc-compile/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
-          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
-        ].join(' '),
-      ],
-    }),
-  });
-});
-
-test('esbuild bundling with pre-compilations without tsconfig', () => {
-  expect(() => {
-    Bundling.bundle({
-      entry,
-      projectRoot,
-      depsLockFilePath,
-      runtime: Runtime.NODEJS_14_X,
-      forceDockerBundling: true,
-      preCompilation: true,
-    });
-  }).toThrow('preCompilation cannot be used when tsconfig is undefined');
-});
-
 test('esbuild bundling source map default', () => {
   Bundling.bundle({
     entry,
@@ -571,3 +531,93 @@ test('esbuild bundling with projectRoot and externals and dependencies', () => {
     }),
   });
 });
+
+test('esbuild bundling with pre compilations', () => {
+  jest.spyOn(util, 'findUp').mockReturnValueOnce(tsconfig);
+  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({});
+
+  Bundling.bundle({
+    entry,
+    projectRoot,
+    depsLockFilePath,
+    runtime: Runtime.NODEJS_14_X,
+    forceDockerBundling: true,
+    tsconfig,
+    preCompilation: true,
+  });
+
+  // Correctly bundles with esbuild
+  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
+    assetHashType: AssetHashType.OUTPUT,
+    bundling: expect.objectContaining({
+      command: [
+        'bash', '-c',
+        [
+          'tsc --project /asset-input/lib/custom-tsconfig.ts &&',
+          'esbuild --bundle \"/asset-input/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
+          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
+        ].join(' '),
+      ],
+    }),
+  });
+});
+
+test('esbuild bundling with pre compilations ( should skip preCompilation as already compiled )', () => {
+  jest.spyOn(util, 'findUp').mockReturnValueOnce(tsconfig);
+  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({});
+
+  Bundling.bundle({
+    entry,
+    projectRoot,
+    depsLockFilePath,
+    runtime: Runtime.NODEJS_14_X,
+    forceDockerBundling: true,
+    tsconfig,
+    preCompilation: true,
+  });
+
+  // Correctly bundles with esbuild
+  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
+    assetHashType: AssetHashType.OUTPUT,
+    bundling: expect.objectContaining({
+      command: [
+        'bash', '-c',
+        [
+          'esbuild --bundle \"/asset-input/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
+          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
+        ].join(' '),
+      ],
+    }),
+  });
+});
+
+test('esbuild bundling with pre compilations and tsc compiler options ', () => {
+  Bundling.clearTscCompilationCache();
+  jest.spyOn(util, 'findUp').mockReturnValueOnce(tsconfig);
+  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({ rootDir: 'src', outDir: 'dist' });
+
+  Bundling.bundle({
+    entry,
+    projectRoot,
+    depsLockFilePath,
+    runtime: Runtime.NODEJS_14_X,
+    forceDockerBundling: true,
+    tsconfig,
+    preCompilation: true,
+  });
+
+  // Correctly bundles with esbuild
+  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
+    assetHashType: AssetHashType.OUTPUT,
+    bundling: expect.objectContaining({
+      command: [
+        'bash', '-c',
+        [
+          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/dist/src &&',
+          'esbuild --bundle \"/asset-input/dist/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
+          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
+        ].join(' '),
+      ],
+    }),
+  });
+});
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
index b1bf269a2766a..f4aa1eaee7693 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
@@ -1,6 +1,6 @@
 import * as child_process from 'child_process';
 import * as path from 'path';
-import { callsites, exec, extractDependencies, extractRootDir, findUp } from '../lib/util';
+import { callsites, exec, extractDependencies, extractCompilerOptions, findUp } from '../lib/util';
 
 beforeEach(() => {
   jest.clearAllMocks();
@@ -121,10 +121,10 @@ describe('extractDependencies', () => {
   });
 });
 
-describe('extractRootDir', () => {
-  test('with rootDir defined in tsconfig.json', () => {
-    expect(extractRootDir(
+describe('tsconfig', () => {
+  test('extract compiler options from tsconfig.json', () => {
+    expect(extractCompilerOptions(
       path.join(__dirname, '../tsconfig.json'),
-    )).toEqual(undefined);
+    )).toBeDefined();
   });
 });

From 4817f6277121d36e395106ca3a29ba910ccb2ced Mon Sep 17 00:00:00 2001
From: Hassan Azhar <57677979+hassanazharkhan@users.noreply.github.com>
Date: Fri, 8 Oct 2021 05:25:06 +0500
Subject: [PATCH 06/15] Update README.md

---
 packages/@aws-cdk/aws-lambda-nodejs/README.md | 2 --
 1 file changed, 2 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/README.md b/packages/@aws-cdk/aws-lambda-nodejs/README.md
index 15b2ade10d8dd..0722aab4d935a 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/README.md
+++ b/packages/@aws-cdk/aws-lambda-nodejs/README.md
@@ -234,13 +234,11 @@ see <https://github.com/aws/aws-cdk/issues/13767>.
 new lambda.NodejsFunction(this, 'my-handler', {
   bundling: {
     preCompilation: true,
-    tsconfig: 'tsconfig.json'
   },
 });
 ```
 
 `tsconfig` is required to enable `preCompilation` as `tsc` will use your `tsconfig` for transpilation. 
-Output of the transpilation will be found under `cdk.out/tsc-compile`
 
 ## Customizing Docker bundling
 

From 64af4f111a74de200f29c3a3a50dbdadccc7527e Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Tue, 12 Oct 2021 03:03:55 +0500
Subject: [PATCH 07/15] PR Feedback

---
 .../aws-lambda-nodejs/lib/bundling.ts         | 26 +++++-----
 .../aws-lambda-nodejs/test/bundling.test.ts   | 49 +++++++++++++++++--
 2 files changed, 60 insertions(+), 15 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index 422a91c01fba6..2a270831a0009 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -144,24 +144,26 @@ export class Bundling implements cdk.BundlingOptions {
 
   private createBundlingCommand(options: BundlingCommandOptions): string {
     const pathJoin = osPathJoin(options.osPlatform);
-    const tsconfig = pathJoin(options.inputDir, this.relativeTsconfigPath ?? 'tsconfig.json');
-
     let tscCommand: string[] = [];
     let relativeEntryPath = this.relativeEntryPath;
 
     if (this.props.preCompilation) {
-      if (tsconfig) {
-        const { rootDir = '', outDir = '' } = extractCompilerOptions(tsconfig);
-        relativeEntryPath = pathJoin(outDir, relativeEntryPath).replace(/\.ts(x?)$/, '.js$1');
+      const tsconfig = this.relativeTsconfigPath ?
+        pathJoin(options.inputDir, this.relativeTsconfigPath) :
+        findUp('tsconfig.json', path.dirname(this.props.entry));
 
-        if (!Bundling.tscCompiled) {
+      if (!tsconfig) {
+        throw new Error('Unable to find tsconfig, please specify the prop: tsconfig');
+      }
 
-          tscCommand = [
-            `${options.tscRunner} --project ${tsconfig}`,
-            ...outDir ? [`--outDir ${pathJoin(options.inputDir, outDir, rootDir)}`] : [],
-          ];
-          Bundling.tscCompiled = true;
-        }
+      const { rootDir = '', outDir = '' } = extractCompilerOptions(tsconfig);
+      relativeEntryPath = pathJoin(outDir, this.relativeEntryPath).replace(/\.ts(x?)$/, '.js$1');
+      if (!Bundling.tscCompiled) {
+        tscCommand = [
+          ...[`${options.tscRunner} --project ${tsconfig}`],
+          ...outDir ? [`--outDir ${pathJoin(options.inputDir, outDir, rootDir)}`] : [],
+        ];
+        Bundling.tscCompiled = true;
       }
     }
 
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index 2c0c6fdb42e3d..f782538172440 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -593,8 +593,7 @@ test('esbuild bundling with pre compilations ( should skip preCompilation as alr
 
 test('esbuild bundling with pre compilations and tsc compiler options ', () => {
   Bundling.clearTscCompilationCache();
-  jest.spyOn(util, 'findUp').mockReturnValueOnce(tsconfig);
-  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({ rootDir: 'src', outDir: 'dist' });
+  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({ rootDir: 'lib', outDir: 'dist' });
 
   Bundling.bundle({
     entry,
@@ -613,7 +612,7 @@ test('esbuild bundling with pre compilations and tsc compiler options ', () => {
       command: [
         'bash', '-c',
         [
-          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/dist/src &&',
+          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/dist/lib &&',
           'esbuild --bundle \"/asset-input/dist/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
           '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
         ].join(' '),
@@ -621,3 +620,47 @@ test('esbuild bundling with pre compilations and tsc compiler options ', () => {
     }),
   });
 });
+
+test('esbuild bundling with pre compilations and tsc compiler options different combinations ', () => {
+  Bundling.clearTscCompilationCache();
+  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({ rootDir: undefined, outDir: 'dist' });
+
+  Bundling.bundle({
+    entry,
+    projectRoot,
+    depsLockFilePath,
+    runtime: Runtime.NODEJS_14_X,
+    forceDockerBundling: true,
+    tsconfig,
+    preCompilation: true,
+  });
+
+  // Correctly bundles with esbuild
+  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
+    assetHashType: AssetHashType.OUTPUT,
+    bundling: expect.objectContaining({
+      command: [
+        'bash', '-c',
+        [
+          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/dist &&',
+          'esbuild --bundle \"/asset-input/dist/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
+          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
+        ].join(' '),
+      ],
+    }),
+  });
+});
+
+test('esbuild bundling with pre compilations and undefined tsconfig', () => {
+  expect(() => {
+    Bundling.bundle({
+      entry,
+      projectRoot,
+      depsLockFilePath,
+      runtime: Runtime.NODEJS_14_X,
+      forceDockerBundling: true,
+      preCompilation: true,
+    });
+  }).toThrow('Unable to find tsconfig, please specify the prop: tsconfig');
+
+});
\ No newline at end of file

From 34001bf4bcb3914bcccd9794b8bc94472b6e4a4a Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Tue, 12 Oct 2021 14:43:00 +0500
Subject: [PATCH 08/15] fix test cases!

---
 packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index 4e6a376e37038..3c6d1b2b1e288 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -11,8 +11,6 @@ import * as util from '../lib/util';
 
 jest.mock('@aws-cdk/aws-lambda');
 
-// Mock DockerImage.fromAsset() to avoid building the image
-let fromBuildMock: jest.SpyInstance<DockerImage>;
 let detectPackageInstallationMock: jest.SpyInstance<PackageInstallation | undefined>;
 beforeEach(() => {
   jest.clearAllMocks();
@@ -570,6 +568,7 @@ test('esbuild bundling with pre compilations', () => {
     forceDockerBundling: true,
     tsconfig,
     preCompilation: true,
+    architecture: Architecture.X86_64,
   });
 
   // Correctly bundles with esbuild
@@ -600,6 +599,7 @@ test('esbuild bundling with pre compilations ( should skip preCompilation as alr
     forceDockerBundling: true,
     tsconfig,
     preCompilation: true,
+    architecture: Architecture.X86_64,
   });
 
   // Correctly bundles with esbuild
@@ -629,6 +629,7 @@ test('esbuild bundling with pre compilations and tsc compiler options ', () => {
     forceDockerBundling: true,
     tsconfig,
     preCompilation: true,
+    architecture: Architecture.X86_64,
   });
 
   // Correctly bundles with esbuild
@@ -659,6 +660,7 @@ test('esbuild bundling with pre compilations and tsc compiler options different
     forceDockerBundling: true,
     tsconfig,
     preCompilation: true,
+    architecture: Architecture.X86_64,
   });
 
   // Correctly bundles with esbuild
@@ -686,6 +688,7 @@ test('esbuild bundling with pre compilations and undefined tsconfig', () => {
       runtime: Runtime.NODEJS_14_X,
       forceDockerBundling: true,
       preCompilation: true,
+      architecture: Architecture.X86_64,
     });
   }).toThrow('Unable to find tsconfig, please specify the prop: tsconfig');
 

From 243fe093f7455cd5ae19b839ae8c80035ddaba01 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Wed, 13 Oct 2021 20:38:41 +0500
Subject: [PATCH 09/15] fix preCompilation!

---
 .../aws-lambda-nodejs/lib/bundling.ts         | 10 ++--
 .../aws-lambda-nodejs/test/bundling.test.ts   | 54 +++----------------
 2 files changed, 13 insertions(+), 51 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index 36d262ca57963..d42304cd77d0d 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -5,7 +5,7 @@ import * as cdk from '@aws-cdk/core';
 import { PackageInstallation } from './package-installation';
 import { PackageManager } from './package-manager';
 import { BundlingOptions, SourceMapMode } from './types';
-import { exec, extractDependencies, extractCompilerOptions, findUp } from './util';
+import { exec, extractDependencies, findUp } from './util';
 
 const ESBUILD_MAJOR_VERSION = '0';
 
@@ -162,12 +162,12 @@ export class Bundling implements cdk.BundlingOptions {
         throw new Error('Unable to find tsconfig, please specify the prop: tsconfig');
       }
 
-      const { rootDir = '', outDir = '' } = extractCompilerOptions(tsconfig);
-      relativeEntryPath = pathJoin(outDir, this.relativeEntryPath).replace(/\.ts(x?)$/, '.js$1');
+
+      relativeEntryPath = relativeEntryPath.replace(/\.ts(x?)$/, '.js$1');
       if (!Bundling.tscCompiled) {
         tscCommand = [
-          ...[`${options.tscRunner} --project ${tsconfig}`],
-          ...outDir ? [`--outDir ${pathJoin(options.inputDir, outDir, rootDir)}`] : [],
+          // Setting explicity rootDir and outDir, so that the compiled js file always end up next ts file.
+          ...[`${options.tscRunner} --project ${tsconfig} --rootDir ./ --outDir ./`],
         ];
         Bundling.tscCompiled = true;
       }
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index 3c6d1b2b1e288..fbe005e502c63 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -557,9 +557,6 @@ test('esbuild bundling with projectRoot and externals and dependencies', () => {
 });
 
 test('esbuild bundling with pre compilations', () => {
-  jest.spyOn(util, 'findUp').mockReturnValueOnce(tsconfig);
-  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({});
-
   Bundling.bundle({
     entry,
     projectRoot,
@@ -578,7 +575,7 @@ test('esbuild bundling with pre compilations', () => {
       command: [
         'bash', '-c',
         [
-          'tsc --project /asset-input/lib/custom-tsconfig.ts &&',
+          'tsc --project /asset-input/lib/custom-tsconfig.ts --rootDir ./ --outDir ./ &&',
           'esbuild --bundle \"/asset-input/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
           '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
         ].join(' '),
@@ -587,10 +584,7 @@ test('esbuild bundling with pre compilations', () => {
   });
 });
 
-test('esbuild bundling with pre compilations ( should skip preCompilation as already compiled )', () => {
-  jest.spyOn(util, 'findUp').mockReturnValueOnce(tsconfig);
-  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({});
-
+test('esbuild bundling with pre compilations ( Should skip preCompilation as already compiled )', () => {
   Bundling.bundle({
     entry,
     projectRoot,
@@ -617,40 +611,9 @@ test('esbuild bundling with pre compilations ( should skip preCompilation as alr
   });
 });
 
-test('esbuild bundling with pre compilations and tsc compiler options ', () => {
-  Bundling.clearTscCompilationCache();
-  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({ rootDir: 'lib', outDir: 'dist' });
-
-  Bundling.bundle({
-    entry,
-    projectRoot,
-    depsLockFilePath,
-    runtime: Runtime.NODEJS_14_X,
-    forceDockerBundling: true,
-    tsconfig,
-    preCompilation: true,
-    architecture: Architecture.X86_64,
-  });
-
-  // Correctly bundles with esbuild
-  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
-    assetHashType: AssetHashType.OUTPUT,
-    bundling: expect.objectContaining({
-      command: [
-        'bash', '-c',
-        [
-          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/dist/lib &&',
-          'esbuild --bundle \"/asset-input/dist/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
-          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
-        ].join(' '),
-      ],
-    }),
-  });
-});
-
-test('esbuild bundling with pre compilations and tsc compiler options different combinations ', () => {
+test('esbuild bundling with pre compilations with undefined tsconfig ( Should find in root directory )', () => {
   Bundling.clearTscCompilationCache();
-  jest.spyOn(util, 'extractCompilerOptions').mockReturnValueOnce({ rootDir: undefined, outDir: 'dist' });
+  jest.spyOn(util, 'findUp').mockReturnValueOnce('/asset-input/lib/custom-tsconfig.ts');
 
   Bundling.bundle({
     entry,
@@ -658,7 +621,6 @@ test('esbuild bundling with pre compilations and tsc compiler options different
     depsLockFilePath,
     runtime: Runtime.NODEJS_14_X,
     forceDockerBundling: true,
-    tsconfig,
     preCompilation: true,
     architecture: Architecture.X86_64,
   });
@@ -670,16 +632,16 @@ test('esbuild bundling with pre compilations and tsc compiler options different
       command: [
         'bash', '-c',
         [
-          'tsc --project /asset-input/lib/custom-tsconfig.ts --outDir /asset-input/dist &&',
-          'esbuild --bundle \"/asset-input/dist/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
-          '--external:aws-sdk --tsconfig=/asset-input/lib/custom-tsconfig.ts',
+          'tsc --project /asset-input/lib/custom-tsconfig.ts --rootDir ./ --outDir ./ &&',
+          'esbuild --bundle \"/asset-input/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
+          '--external:aws-sdk',
         ].join(' '),
       ],
     }),
   });
 });
 
-test('esbuild bundling with pre compilations and undefined tsconfig', () => {
+test('esbuild bundling with pre compilations and undefined tsconfig ( Should throw) ', () => {
   expect(() => {
     Bundling.bundle({
       entry,

From 9ca84b2c1ae40b221228446bc4d5159687b9d7fd Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Wed, 13 Oct 2021 20:44:15 +0500
Subject: [PATCH 10/15] fix comment

---
 packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index d42304cd77d0d..cdb6eccc7f191 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -166,7 +166,7 @@ export class Bundling implements cdk.BundlingOptions {
       relativeEntryPath = relativeEntryPath.replace(/\.ts(x?)$/, '.js$1');
       if (!Bundling.tscCompiled) {
         tscCommand = [
-          // Setting explicity rootDir and outDir, so that the compiled js file always end up next ts file.
+          // Intentionally Setting rootDir and outDir, so that the compiled js file always end up next ts file.
           ...[`${options.tscRunner} --project ${tsconfig} --rootDir ./ --outDir ./`],
         ];
         Bundling.tscCompiled = true;

From f6484dcef4c55ab3d85cd8386f7a476088d3726d Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Wed, 13 Oct 2021 20:52:09 +0500
Subject: [PATCH 11/15] Cleanup!

---
 .../@aws-cdk/aws-lambda-nodejs/lib/bundling.ts  |  2 --
 packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts | 17 -----------------
 .../aws-lambda-nodejs/test/util.test.ts         |  9 +--------
 3 files changed, 1 insertion(+), 27 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index cdb6eccc7f191..a62b30aaf28af 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -162,7 +162,6 @@ export class Bundling implements cdk.BundlingOptions {
         throw new Error('Unable to find tsconfig, please specify the prop: tsconfig');
       }
 
-
       relativeEntryPath = relativeEntryPath.replace(/\.ts(x?)$/, '.js$1');
       if (!Bundling.tscCompiled) {
         tscCommand = [
@@ -173,7 +172,6 @@ export class Bundling implements cdk.BundlingOptions {
       }
     }
 
-
     const loaders = Object.entries(this.props.loader ?? {});
     const defines = Object.entries(this.props.define ?? {});
 
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
index 5717456608a56..bb59af6c34eaa 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
@@ -111,20 +111,3 @@ export function extractDependencies(pkgPath: string, modules: string[]): { [key:
   return dependencies;
 }
 
-/**
- * Returns compilerOptions from tsconfig.json
- */
-export function extractCompilerOptions(tsconfigPath: string, previous?: { [key: string]: string }): any | undefined {
-  try {
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const { extends: extendedConfig, compilerOptions: current } = require(tsconfigPath);
-    const merged = { ...previous, ...current };
-    if (extendedConfig) {
-      return extractCompilerOptions(path.resolve(tsconfigPath.replace(/[^\/]+$/, ''), extendedConfig), merged);
-    }
-    return merged;
-
-  } catch (err) {
-    return;
-  }
-}
\ No newline at end of file
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
index f4aa1eaee7693..af627c8f102a7 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
@@ -1,6 +1,6 @@
 import * as child_process from 'child_process';
 import * as path from 'path';
-import { callsites, exec, extractDependencies, extractCompilerOptions, findUp } from '../lib/util';
+import { callsites, exec, extractDependencies, findUp } from '../lib/util';
 
 beforeEach(() => {
   jest.clearAllMocks();
@@ -121,10 +121,3 @@ describe('extractDependencies', () => {
   });
 });
 
-describe('tsconfig', () => {
-  test('extract compiler options from tsconfig.json', () => {
-    expect(extractCompilerOptions(
-      path.join(__dirname, '../tsconfig.json'),
-    )).toBeDefined();
-  });
-});

From dc51d9ce1a293eff1822f79a7d217a8d8e9b4f4c Mon Sep 17 00:00:00 2001
From: Hassan Azhar <57677979+hassanazharkhan@users.noreply.github.com>
Date: Wed, 13 Oct 2021 20:53:15 +0500
Subject: [PATCH 12/15] Update util.test.ts

---
 packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
index af627c8f102a7..4962ed203b31f 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts
@@ -120,4 +120,3 @@ describe('extractDependencies', () => {
     )).toThrow(/Cannot extract version for module 'unknown'/);
   });
 });
-

From a5eaef2374f9fa40f44db1c43fd1ae0b45d0a676 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Fri, 15 Oct 2021 18:28:19 +0500
Subject: [PATCH 13/15] Integ test

---
 .../aws-lambda-nodejs/lib/bundling.ts         |  20 +-
 .../@aws-cdk/aws-lambda-nodejs/lib/util.ts    |   1 -
 .../aws-lambda-nodejs/test/bundling.test.ts   |  16 +-
 .../integ-handlers/ts-decorator-handler.ts    |  23 ++
 .../test/integ.compilations.expected.json     | 198 ++++++++++++++++++
 .../test/integ.compilations.ts                |  39 ++++
 6 files changed, 278 insertions(+), 19 deletions(-)
 create mode 100644 packages/@aws-cdk/aws-lambda-nodejs/test/integ-handlers/ts-decorator-handler.ts
 create mode 100644 packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.expected.json
 create mode 100644 packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.ts

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index a62b30aaf28af..e2d84e3f3e262 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -150,24 +150,24 @@ export class Bundling implements cdk.BundlingOptions {
 
   private createBundlingCommand(options: BundlingCommandOptions): string {
     const pathJoin = osPathJoin(options.osPlatform);
-    let tscCommand: string[] = [];
+    let tscCommand: string = '';
     let relativeEntryPath = this.relativeEntryPath;
 
     if (this.props.preCompilation) {
-      const tsconfig = this.relativeTsconfigPath ?
-        pathJoin(options.inputDir, this.relativeTsconfigPath) :
-        findUp('tsconfig.json', path.dirname(this.props.entry));
 
+      let tsconfig = this.relativeTsconfigPath;
       if (!tsconfig) {
-        throw new Error('Unable to find tsconfig, please specify the prop: tsconfig');
+        const findConfig = findUp('tsconfig.json', path.dirname(this.props.entry));
+        if (!findConfig) {
+          throw new Error('Cannot find a tsconfig.json, please specify the prop: tsconfig');
+        }
+        tsconfig = path.relative(this.projectRoot, findConfig);
       }
 
       relativeEntryPath = relativeEntryPath.replace(/\.ts(x?)$/, '.js$1');
       if (!Bundling.tscCompiled) {
-        tscCommand = [
-          // Intentionally Setting rootDir and outDir, so that the compiled js file always end up next ts file.
-          ...[`${options.tscRunner} --project ${tsconfig} --rootDir ./ --outDir ./`],
-        ];
+        // Intentionally Setting rootDir and outDir, so that the compiled js file always end up next ts file.
+        tscCommand = `${options.tscRunner} --project ${pathJoin(options.inputDir, tsconfig)} --rootDir ./ --outDir ./`;
         Bundling.tscCompiled = true;
       }
     }
@@ -228,7 +228,7 @@ export class Bundling implements cdk.BundlingOptions {
 
     return chain([
       ...this.props.commandHooks?.beforeBundling(options.inputDir, options.outputDir) ?? [],
-      tscCommand.join(' '),
+      tscCommand,
       esbuildCommand.join(' '),
       ...(this.props.nodeModules && this.props.commandHooks?.beforeInstall(options.inputDir, options.outputDir)) ?? [],
       depsCommand,
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
index bb59af6c34eaa..5ead91793e93b 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts
@@ -110,4 +110,3 @@ export function extractDependencies(pkgPath: string, modules: string[]): { [key:
 
   return dependencies;
 }
-
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index fbe005e502c63..fe6ce1de29786 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -613,12 +613,12 @@ test('esbuild bundling with pre compilations ( Should skip preCompilation as alr
 
 test('esbuild bundling with pre compilations with undefined tsconfig ( Should find in root directory )', () => {
   Bundling.clearTscCompilationCache();
-  jest.spyOn(util, 'findUp').mockReturnValueOnce('/asset-input/lib/custom-tsconfig.ts');
+  const packageLock = path.join(__dirname, '..', 'package-lock.json');
 
   Bundling.bundle({
-    entry,
-    projectRoot,
-    depsLockFilePath,
+    entry: __filename.replace('.js', '.ts'),
+    projectRoot: path.dirname(packageLock),
+    depsLockFilePath: packageLock,
     runtime: Runtime.NODEJS_14_X,
     forceDockerBundling: true,
     preCompilation: true,
@@ -626,14 +626,14 @@ test('esbuild bundling with pre compilations with undefined tsconfig ( Should fi
   });
 
   // Correctly bundles with esbuild
-  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(depsLockFilePath), {
+  expect(Code.fromAsset).toHaveBeenCalledWith(path.dirname(packageLock), {
     assetHashType: AssetHashType.OUTPUT,
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
         [
-          'tsc --project /asset-input/lib/custom-tsconfig.ts --rootDir ./ --outDir ./ &&',
-          'esbuild --bundle \"/asset-input/lib/handler.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
+          'tsc --project /asset-input/tsconfig.json --rootDir ./ --outDir ./ &&',
+          'esbuild --bundle \"/asset-input/test/bundling.test.js\" --target=node14 --platform=node --outfile=\"/asset-output/index.js\"',
           '--external:aws-sdk',
         ].join(' '),
       ],
@@ -652,6 +652,6 @@ test('esbuild bundling with pre compilations and undefined tsconfig ( Should thr
       preCompilation: true,
       architecture: Architecture.X86_64,
     });
-  }).toThrow('Unable to find tsconfig, please specify the prop: tsconfig');
+  }).toThrow('Cannot find a tsconfig.json, please specify the prop: tsconfig');
 
 });
\ No newline at end of file
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/integ-handlers/ts-decorator-handler.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/integ-handlers/ts-decorator-handler.ts
new file mode 100644
index 0000000000000..99ca5ee8ceec1
--- /dev/null
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/integ-handlers/ts-decorator-handler.ts
@@ -0,0 +1,23 @@
+function enumerable(value: boolean) {
+  return function (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) {
+    descriptor.enumerable = value;
+  };
+}
+
+class Greeter {
+  greeting: string;
+  constructor(message: string) {
+    this.greeting = message;
+  }
+
+  @enumerable(false)
+  greet() {
+    return 'Hello, ' + this.greeting;
+  }
+}
+
+
+export async function handler(): Promise<void> {
+  const message = new Greeter('World').greet();
+  console.log(message); // eslint-disable-line no-console
+}
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.expected.json b/packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.expected.json
new file mode 100644
index 0000000000000..de56ccb33b617
--- /dev/null
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.expected.json
@@ -0,0 +1,198 @@
+{
+  "Resources": {
+    "tsdecoratorhandlerServiceRole61E9E52C": {
+      "Type": "AWS::IAM::Role",
+      "Properties": {
+        "AssumeRolePolicyDocument": {
+          "Statement": [
+            {
+              "Action": "sts:AssumeRole",
+              "Effect": "Allow",
+              "Principal": {
+                "Service": "lambda.amazonaws.com"
+              }
+            }
+          ],
+          "Version": "2012-10-17"
+        },
+        "ManagedPolicyArns": [
+          {
+            "Fn::Join": [
+              "",
+              [
+                "arn:",
+                {
+                  "Ref": "AWS::Partition"
+                },
+                ":iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
+              ]
+            ]
+          }
+        ]
+      }
+    },
+    "tsdecoratorhandlerC8E2F076": {
+      "Type": "AWS::Lambda::Function",
+      "Properties": {
+        "Code": {
+          "S3Bucket": {
+            "Ref": "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3Bucket2B516B38"
+          },
+          "S3Key": {
+            "Fn::Join": [
+              "",
+              [
+                {
+                  "Fn::Select": [
+                    0,
+                    {
+                      "Fn::Split": [
+                        "||",
+                        {
+                          "Ref": "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3VersionKey4B530CD7"
+                        }
+                      ]
+                    }
+                  ]
+                },
+                {
+                  "Fn::Select": [
+                    1,
+                    {
+                      "Fn::Split": [
+                        "||",
+                        {
+                          "Ref": "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3VersionKey4B530CD7"
+                        }
+                      ]
+                    }
+                  ]
+                }
+              ]
+            ]
+          }
+        },
+        "Role": {
+          "Fn::GetAtt": [
+            "tsdecoratorhandlerServiceRole61E9E52C",
+            "Arn"
+          ]
+        },
+        "Environment": {
+          "Variables": {
+            "AWS_NODEJS_CONNECTION_REUSE_ENABLED": "1"
+          }
+        },
+        "Handler": "index.handler",
+        "Runtime": "nodejs14.x"
+      },
+      "DependsOn": [
+        "tsdecoratorhandlerServiceRole61E9E52C"
+      ]
+    },
+    "tsdecoratorhandlertsconfigServiceRoleC4AE481E": {
+      "Type": "AWS::IAM::Role",
+      "Properties": {
+        "AssumeRolePolicyDocument": {
+          "Statement": [
+            {
+              "Action": "sts:AssumeRole",
+              "Effect": "Allow",
+              "Principal": {
+                "Service": "lambda.amazonaws.com"
+              }
+            }
+          ],
+          "Version": "2012-10-17"
+        },
+        "ManagedPolicyArns": [
+          {
+            "Fn::Join": [
+              "",
+              [
+                "arn:",
+                {
+                  "Ref": "AWS::Partition"
+                },
+                ":iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
+              ]
+            ]
+          }
+        ]
+      }
+    },
+    "tsdecoratorhandlertsconfig68EC191E": {
+      "Type": "AWS::Lambda::Function",
+      "Properties": {
+        "Code": {
+          "S3Bucket": {
+            "Ref": "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3Bucket2B516B38"
+          },
+          "S3Key": {
+            "Fn::Join": [
+              "",
+              [
+                {
+                  "Fn::Select": [
+                    0,
+                    {
+                      "Fn::Split": [
+                        "||",
+                        {
+                          "Ref": "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3VersionKey4B530CD7"
+                        }
+                      ]
+                    }
+                  ]
+                },
+                {
+                  "Fn::Select": [
+                    1,
+                    {
+                      "Fn::Split": [
+                        "||",
+                        {
+                          "Ref": "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3VersionKey4B530CD7"
+                        }
+                      ]
+                    }
+                  ]
+                }
+              ]
+            ]
+          }
+        },
+        "Role": {
+          "Fn::GetAtt": [
+            "tsdecoratorhandlertsconfigServiceRoleC4AE481E",
+            "Arn"
+          ]
+        },
+        "Environment": {
+          "Variables": {
+            "AWS_NODEJS_CONNECTION_REUSE_ENABLED": "1"
+          }
+        },
+        "Handler": "index.handler",
+        "Runtime": "nodejs14.x"
+      },
+      "DependsOn": [
+        "tsdecoratorhandlertsconfigServiceRoleC4AE481E"
+      ]
+    }
+  },
+  "Parameters": {
+    "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3Bucket2B516B38": {
+      "Type": "String",
+      "Description": "S3 bucket for asset \"482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283f\""
+    },
+    "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fS3VersionKey4B530CD7": {
+      "Type": "String",
+      "Description": "S3 key for asset version \"482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283f\""
+    },
+    "AssetParameters482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283fArtifactHash237F55B4": {
+      "Type": "String",
+      "Description": "Artifact hash for asset \"482454f5e1d850303130cf1cdbee1376fca84deaf9ccfa2c4cf8a246d415283f\""
+    }
+  }
+}
\ No newline at end of file
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.ts
new file mode 100644
index 0000000000000..2c78bde18bbf7
--- /dev/null
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/integ.compilations.ts
@@ -0,0 +1,39 @@
+/// !cdk-integ pragma:ignore-assets
+import * as path from 'path';
+import { Runtime } from '@aws-cdk/aws-lambda';
+import { App, Stack, StackProps } from '@aws-cdk/core';
+import { Construct } from 'constructs';
+import * as lambda from '../lib';
+
+class TestStack extends Stack {
+  constructor(scope: Construct, id: string, props?: StackProps) {
+    super(scope, id, props);
+
+    new lambda.NodejsFunction(this, 'ts-decorator-handler', {
+      entry: path.join(__dirname, 'integ-handlers/ts-decorator-handler.ts'),
+      bundling: {
+        minify: true,
+        sourceMap: true,
+        sourceMapMode: lambda.SourceMapMode.BOTH,
+        preCompilation: true,
+      },
+      runtime: Runtime.NODEJS_14_X,
+    });
+
+    new lambda.NodejsFunction(this, 'ts-decorator-handler-tsconfig', {
+      entry: path.join(__dirname, 'integ-handlers/ts-decorator-handler.ts'),
+      bundling: {
+        minify: true,
+        sourceMap: true,
+        sourceMapMode: lambda.SourceMapMode.BOTH,
+        tsconfig: path.join(__dirname, '..', 'tsconfig.json'),
+        preCompilation: true,
+      },
+      runtime: Runtime.NODEJS_14_X,
+    });
+  }
+}
+
+const app = new App();
+new TestStack(app, 'cdk-integ-compilations-lambda-nodejs');
+app.synth();

From b1cdca6769ded1d601ede06a413094bc13a084c1 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Sat, 16 Oct 2021 16:47:24 +0500
Subject: [PATCH 14/15] PR feedback!

---
 .../aws-lambda-nodejs/test/bundling.test.ts      | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
index fe6ce1de29786..02b6030ae3e12 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts
@@ -9,7 +9,6 @@ import { PackageInstallation } from '../lib/package-installation';
 import { LogLevel, SourceMapMode } from '../lib/types';
 import * as util from '../lib/util';
 
-jest.mock('@aws-cdk/aws-lambda');
 
 let detectPackageInstallationMock: jest.SpyInstance<PackageInstallation | undefined>;
 beforeEach(() => {
@@ -19,17 +18,19 @@ beforeEach(() => {
   Bundling.clearEsbuildInstallationCache();
   Bundling.clearTscInstallationCache();
 
+  jest.spyOn(Code, 'fromAsset');
+
+  detectPackageInstallationMock = jest.spyOn(PackageInstallation, 'detect').mockReturnValue({
+    isLocal: true,
+    version: '0.8.8',
+  });
+
   jest.spyOn(DockerImage, 'fromBuild').mockReturnValue({
     image: 'built-image',
     cp: () => 'dest-path',
     run: () => {},
     toJSON: () => 'built-image',
   });
-
-  detectPackageInstallationMock = jest.spyOn(PackageInstallation, 'detect').mockReturnValue({
-    isLocal: true,
-    version: '0.8.8',
-  });
 });
 
 let projectRoot = '/project';
@@ -582,9 +583,7 @@ test('esbuild bundling with pre compilations', () => {
       ],
     }),
   });
-});
 
-test('esbuild bundling with pre compilations ( Should skip preCompilation as already compiled )', () => {
   Bundling.bundle({
     entry,
     projectRoot,
@@ -609,6 +608,7 @@ test('esbuild bundling with pre compilations ( Should skip preCompilation as alr
       ],
     }),
   });
+
 });
 
 test('esbuild bundling with pre compilations with undefined tsconfig ( Should find in root directory )', () => {

From 3d2535b36112302942a1603fb2bb3a3f841337e7 Mon Sep 17 00:00:00 2001
From: Hassan Azhar Khan <hassanazharkhan@gmail.com>
Date: Tue, 26 Oct 2021 02:47:30 +0500
Subject: [PATCH 15/15] PR feedback!

---
 packages/@aws-cdk/aws-lambda-nodejs/README.md       | 8 ++++----
 packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts | 2 +-
 packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts    | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/@aws-cdk/aws-lambda-nodejs/README.md b/packages/@aws-cdk/aws-lambda-nodejs/README.md
index f82e72e07443e..6e901612539d8 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/README.md
+++ b/packages/@aws-cdk/aws-lambda-nodejs/README.md
@@ -227,9 +227,9 @@ container for Docker bundling or on the host OS for local bundling.
 
 ## Pre Compilation with TSC
 
-It is possible to run compilation using typescript compiler before bundling, 
-this is for adding support of `emitDecoratorMetadata` which `esbuild` doesn't support it natively.
-see <https://github.com/aws/aws-cdk/issues/13767>.
+In some cases, `esbuild` may not yet support some newer features of the typescript language, such as,
+[`emitDecoratorMetadata`](https://www.typescriptlang.org/tsconfig#emitDecoratorMetadata).
+In such cases, it is possible to run pre-compilation using `tsc` by setting the `preCompilation` flag.
 
 ```ts
 new lambda.NodejsFunction(this, 'my-handler', {
@@ -239,7 +239,7 @@ new lambda.NodejsFunction(this, 'my-handler', {
 });
 ```
 
-`tsconfig` is required to enable `preCompilation` as `tsc` will use your `tsconfig` for transpilation. 
+Note: A [`tsconfig.json` file](https://www.typescriptlang.org/docs/handbook/tsconfig-json.html) is required 
 
 ## Customizing Docker bundling
 
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
index e2d84e3f3e262..e53e5e092de7c 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts
@@ -39,7 +39,7 @@ export interface BundlingProps extends BundlingOptions {
   readonly projectRoot: string;
 
   /**
-   * Force pre-transpilation using TSC before bundling
+   * Run compilation using `tsc` before bundling
    */
   readonly preCompilation?: boolean
 
diff --git a/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts b/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
index d217601fcd4b2..6bd26c846c6fe 100644
--- a/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
+++ b/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts
@@ -198,7 +198,7 @@ export interface BundlingOptions {
   readonly forceDockerBundling?: boolean;
 
   /**
-  * Force pre-transpilation using TSC before running file through bundling step.
+  * Run compilation using tsc before running file through bundling step.
   * This usually is not required unless you are using new experimental features that
   * are only supported by typescript's `tsc` compiler.
   * One example of such feature is `emitDecoratorMetadata`.