expose transform and resolveapi from parcel

packages/core/core/src/Parcel.js

@@ -1,12 +1,17 @@
 // @flow strict-local
 
 import type {
+  Asset,
   AsyncSubscription,
   BuildEvent,
   BuildSuccessEvent,
   InitialParcelOptions,
   PackagedBundle as IPackagedBundle,
+  ParcelTransformOptions,
+  ParcelResolveOptions,
+  ParcelResolveResult,
 } from '@parcel/types';
+import path from 'path';
 import type {ParcelOptions} from './types';
 // eslint-disable-next-line no-unused-vars
 import type {FarmOptions, SharedReference} from '@parcel/workers';
@@ -37,10 +42,18 @@ import RequestTracker, {
 } from './RequestTracker';
 import createValidationRequest from './requests/ValidationRequest';
 import createParcelBuildRequest from './requests/ParcelBuildRequest';
+import createAssetRequest from './requests/AssetRequest';
+import createPathRequest from './requests/PathRequest';
+import {createEnvironment} from './Environment';
+import {createDependency} from './Dependency';
 import {Disposable} from '@parcel/events';
 import {init as initSourcemaps} from '@parcel/source-map';
 import {init as initHash} from '@parcel/hash';
-import {toProjectPath} from './projectPath';
+import {
+  fromProjectPath,
+  toProjectPath,
+  fromProjectPathRelative,
+} from './projectPath';
 import {tracer} from '@parcel/profiler';
 
 registerCoreWithSerializer();
@@ -437,6 +450,78 @@ export default class Parcel {
     logger.info({origin: '@parcel/core', message: 'Taking heap snapshot...'});
     return this.#farm.takeHeapSnapshot();
   }
+
+  async transform(options: ParcelTransformOptions): Promise<Array<Asset>> {
+    if (!this.#initialized) {
+      await this._init();
+    }
+
+    let projectRoot = nullthrows(this.#resolvedOptions).projectRoot;
+    let request = createAssetRequest({
+      ...options,
+      filePath: toProjectPath(projectRoot, options.filePath),
+      optionsRef: this.#optionsRef,
+      env: createEnvironment({
+        ...options.env,
+        loc:
+          options.env?.loc != null
+            ? {
+                ...options.env.loc,
+                filePath: toProjectPath(projectRoot, options.env.loc.filePath),
+              }
+            : undefined,
+      }),
+    });
+
+    let res = await this.#requestTracker.runRequest(request, {force: true});
+    return res.map(asset =>
+      assetFromValue(asset, nullthrows(this.#resolvedOptions)),
+    );
+  }
+
+  async resolve(request: ParcelResolveOptions): Promise<?ParcelResolveResult> {
+    if (!this.#initialized) {
+      await this._init();
+    }
+
+    let projectRoot = nullthrows(this.#resolvedOptions).projectRoot;
+    if (request.resolveFrom == null && path.isAbsolute(request.specifier)) {
+      request.specifier = fromProjectPathRelative(
+        toProjectPath(projectRoot, request.specifier),
+      );
+    }
+
+    let dependency = createDependency(projectRoot, {
+      ...request,
+      env: createEnvironment({
+        ...request.env,
+        loc:
+          request.env?.loc != null
+            ? {
+                ...request.env.loc,
+                filePath: toProjectPath(projectRoot, request.env.loc.filePath),
+              }
+            : undefined,
+      }),
+    });
+
+    let req = createPathRequest({
+      dependency,
+      name: 'test',
+    });
+
+    let res = await this.#requestTracker.runRequest(req, {force: true});
+    if (!res) {
+      return null;
+    }
+
+    return {
+      filePath: fromProjectPath(projectRoot, res.filePath),
+      code: res.code,
+      query: res.query,
+      sideEffects: res.sideEffects,
+    };
+  }
 }
 
 export class BuildError extends ThrowableDiagnostic {

packages/core/core/test/Parcel.test.js

@@ -75,6 +75,59 @@ describe('Parcel', function () {
   });
 });
 
+describe('ParcelAPI', function () {
+  this.timeout(75000);
+
+  let workerFarm;
+  beforeEach(() => {
+    workerFarm = createWorkerFarm();
+  });
+
+  afterEach(() => workerFarm.end());
+
+  describe('parcel.transform()', () => {
+    it('should transforms simple file', async () => {
+      let parcel = createParcel({workerFarm});
+      let res = await parcel.transform({
+        filePath: path.join(__dirname, 'fixtures/parcel/index.js'),
+      });
+      let code = await res[0].getCode();
+      assert(code.includes('exports.default = "test"'));
+    });
+
+    it('should transform with standalone mode', async () => {
+      let parcel = createParcel({workerFarm});
+      let res = await parcel.transform({
+        filePath: path.join(__dirname, 'fixtures/parcel/other.js'),
+        query: 'standalone=true',
+      });
+      let code = await res[0].getCode();
+
+      assert(code.includes('require("./index.js")'));
+      assert(code.includes('new URL("index.js", "file:" + __filename);'));
+      assert(code.includes('import("index.js")'));
+    });
+  });
+
+  describe('parcel.resolve()', () => {
+    it('should resolve dependencies', async () => {
+      let parcel = createParcel({workerFarm});
+      let res = await parcel.resolve({
+        specifier: './other',
+        specifierType: 'esm',
+        resolveFrom: path.join(__dirname, 'fixtures/parcel/index.js'),
+      });
+
+      assert.deepEqual(res, {
+        filePath: path.join(__dirname, 'fixtures/parcel/other.js'),
+        code: undefined,
+        query: undefined,
+        sideEffects: true,
+      });
+    });
+  });
+});
+
 function createParcel(opts?: InitialParcelOptions) {
   return new Parcel({
     entries: [path.join(__dirname, 'fixtures/parcel/index.js')],

packages/core/core/test/fixtures/parcel/index.js

@@ -0,0 +1 @@
+export default 'test';

packages/core/core/test/fixtures/parcel/other.js

@@ -0,0 +1,3 @@
+import * as idx from './index.js';
+new URL('index.js', import.meta.url);
+import('index.js')

packages/core/types/index.js

@@ -645,6 +645,28 @@ export type ASTGenerator = {|
 
 export type BundleBehavior = 'inline' | 'isolated';
 
+export type ParcelTransformOptions = {|
+  filePath: FilePath,
+  code?: string,
+  env?: EnvironmentOptions,
+  pipeline?: ?string,
+  query?: ?string,
+|};
+
+export type ParcelResolveOptions = {|
+  specifier: DependencySpecifier,
+  specifierType: SpecifierType,
+  env?: EnvironmentOptions,
+  resolveFrom?: FilePath,
+|};
+
+export type ParcelResolveResult = {|
+  filePath: FilePath,
+  code?: string,
+  query?: ?string,
+  sideEffects?: boolean,
+|};
+
 /**
  * An asset represents a file or part of a file. It may represent any data type, including source code,
  * binary data, etc. Assets may exist in the file system or may be virtual.

packages/transformers/js/core/src/dependency_collector.rs

@@ -125,15 +125,16 @@ impl<'a> DependencyCollector<'a> {
           None
         }
       }
-      _ => Some(format!(
+      _ if !self.config.standalone => Some(format!(
         "{:x}",
         hash!(format!(
           "{}:{}:{}",
           self.get_project_relative_filename(),
           specifier,
           kind
-        ))
+        )),
       )),
+      _ => None,
     };
 
     self.items.push(DependencyDescriptor {
@@ -158,7 +159,7 @@ impl<'a> DependencyCollector<'a> {
     source_type: SourceType,
   ) -> ast::Expr {
     // If not a library, replace with a require call pointing to a runtime that will resolve the url dynamically.
-    if !self.config.is_library {
+    if !self.config.is_library && !self.config.standalone {
       let placeholder =
         self.add_dependency(specifier.clone(), span, kind, None, false, source_type);
       let specifier = if let Some(placeholder) = placeholder {
@@ -172,13 +173,17 @@ impl<'a> DependencyCollector<'a> {
     // For library builds, we need to create something that can be statically analyzed by another bundler,
     // so rather than replacing with a require call that is resolved by a runtime, replace with a `new URL`
     // call with a placeholder for the relative path to be replaced during packaging.
-    let placeholder = format!(
-      "{:x}",
-      hash!(format!(
-        "parcel_url:{}:{}:{}",
-        self.config.filename, specifier, kind
-      ))
-    );
+    let placeholder = if self.config.standalone {
+      specifier.as_ref().into()
+    } else {
+      format!(
+        "{:x}",
+        hash!(format!(
+          "parcel_url:{}:{}:{}",
+          self.config.filename, specifier, kind
+        ))
+      )
+    };
     self.items.push(DependencyDescriptor {
       kind,
       loc: SourceLocation::from(self.source_map, span),
@@ -666,7 +671,7 @@ impl<'a> Fold for DependencyCollector<'a> {
     // Replace import() with require()
     if kind == DependencyKind::DynamicImport {
       let mut call = node;
-      if !self.config.scope_hoist {
+      if !self.config.scope_hoist && !self.config.standalone {
         let name = match &self.config.source_type {
           SourceType::Module => "require",
           SourceType::Script => "__parcel__require__",
@@ -838,7 +843,7 @@ impl<'a> Fold for DependencyCollector<'a> {
 
       // If this is a library, we will already have a URL object. Otherwise, we need to
       // construct one from the string returned by the JSRuntime.
-      if !self.config.is_library {
+      if !self.config.is_library && !self.config.standalone {
         return Expr::New(NewExpr {
           span: DUMMY_SP,
           callee: Box::new(Expr::Ident(Ident::new(js_word!("URL"), DUMMY_SP))),

packages/transformers/js/core/src/lib.rs

@@ -84,6 +84,7 @@ pub struct Config {
   is_esm_output: bool,
   trace_bailouts: bool,
   is_swc_helpers: bool,
+  standalone: bool,
 }
 
 #[derive(Serialize, Debug, Default)]

packages/transformers/js/src/JSTransformer.js

@@ -442,6 +442,7 @@ export default (new Transformer({
       is_esm_output: asset.env.outputFormat === 'esmodule',
       trace_bailouts: options.logLevel === 'verbose',
       is_swc_helpers: /@swc[/\\]helpers/.test(asset.filePath),
+      standalone: asset.query.has('standalone'),
     });
 
     let convertLoc = (loc): SourceLocation => {