tsc -b parse time is much higher comparing to tsc -p when there is a big d.ts file in node_modules

[zofiag]

Bug Report

Using a third-party package with heavy .d.ts files (eg aws-sdk) slows down tsc -b drastically comparing to tsc -p compilation time.

Comparison of the tsc extendedDiagnostics:

1. tsc -b api/tsconfig.json -w --preserveWatchOutput (or run npm run dev:api:b)
   Much slower after adding a change to the code (eg console.log in a TS file).

Files:                         412
Lines of Library:             8664
Lines of Definitions:       577202
Lines of TypeScript:            34
Lines of JavaScript:             0
Lines of JSON:                   0
Lines of Other:                  0
Nodes of Library:            23282
Nodes of Definitions:      1689642
Nodes of TypeScript:           137
Nodes of JavaScript:             0
Nodes of JSON:                   0
Nodes of Other:                  0
Identifiers:                626998
Symbols:                    367869
Types:                         261
Instantiations:                276
Memory used:               512906K
Assignability cache size:       29
Identity cache size:             1
Subtype cache size:             10
Strict subtype cache size:       0
I/O Read time:               0.24s
Parse time:                  2.67s
ResolveModule time:          0.09s
ResolveTypeReference time:   0.00s
Program time:                3.18s
Bind time:                   0.93s
Check time:                  0.04s
transformTime time:          0.02s
commentTime time:            0.00s
printTime time:              0.04s
Emit time:                   0.04s
Source Map time:             0.00s
I/O Write time:              0.00s
Total time:                  4.20s

2. tsc -p api/tsconfig.json -w --preserveWatchOutput (or run npm run dev:api:p)
   Much faster after adding a change to the code (eg console.log in a TS file).

Files:                         412
Lines of Library:             8664
Lines of Definitions:       577202
Lines of TypeScript:            34
Lines of JavaScript:             0
Lines of JSON:                   0
Lines of Other:                  0
Nodes of Library:            23282
Nodes of Definitions:      1689642
Nodes of TypeScript:           137
Nodes of JavaScript:             0
Nodes of JSON:                   0
Nodes of Other:                  0
Identifiers:                626998
Symbols:                    367869
Types:                         261
Instantiations:                276
Memory used:               513037K
Assignability cache size:       29
Identity cache size:             1
Subtype cache size:             10
Strict subtype cache size:       0
I/O Read time:               0.00s
Parse time:                  0.00s
ResolveModule time:          0.00s
Program time:                0.01s
Bind time:                   0.00s
Check time:                  0.05s
transformTime time:          0.02s
commentTime time:            0.00s
printTime time:              0.05s
Emit time:                   0.05s
Source Map time:             0.00s
I/O Write time:              0.00s
Total time:                  0.11s

🔎 Search Terms

tsc, typescript compiler, build mode, watch mode

🕗 Version & Regression Information

Tested on typescript 3.9.3, 4.4.2, 4.4.3. Same behaviour.

⏯ Playground Link

https://github.com/zofiag/tsc-test - it is a super simple repo project with almost no code, except for the aws-sdk dependency installed that seems to drastically slow down the compilation in build mode.

After cloning the repo, run npm install and:
run npm run dev:api:b for the tsc -b compilation
run npm run dev:api:p for the tsc -p compilation

💻 Code

Project structure:
api/tsconfig.json

{
  "extends": "../tsconfig.base.json",
  "compilerOptions": {
    "rootDir": "src",
    "outDir": "dist"
  },
  "include": [
    "src"
  ],
  "references": [{
      "path": "../libs/shared"
  }]
}

api/src/aws-encryption.ts

import type { KMS } from "aws-sdk";

export class AwsEncryption {
  constructor(private readonly kms: KMS) {}

  encrypt(): Promise<string> {
    return new Promise((resolve, reject) => {
      this.kms.encrypt({ KeyId: "", Plaintext: "" }, (err, data) => {
        if (err) {
          reject(err);
        } else {
          resolve("ok");
        }
      });
    });
  }

  decrypt(): Promise<string> {
    return new Promise((resolve, reject) => {
      this.kms.decrypt({ KeyId: "", CiphertextBlob: "" }, (err, data) => {
        if (err) {
          reject(err);
        } else {
          resolve("ok");
        }
      });
    });
  }
}

shared/tsconfig.json

{
  "extends": "../../tsconfig.base.json",
  "compilerOptions": {
    "rootDir": "src",
    "outDir": "lib"
  },
  "include": [
    "src"
  ],
  "references": []
}

tsconfig.base.json

{
  "compilerOptions": {
    "sourceMap": true,
    "strict": true,
    "moduleResolution": "node",
    "module": "commonjs",
    "esModuleInterop": true,
    "skipLibCheck": true,
    "target": "es6",
    "lib": [
      "es2020"
    ],
    "noFallthroughCasesInSwitch": true,
    "noImplicitReturns": true,
    "noUncheckedIndexedAccess": true,
    "forceConsistentCasingInFileNames": true,
    "allowSyntheticDefaultImports": true,
    "allowJs": false,
    "resolveJsonModule": true,
    "isolatedModules": true,
    "declaration": true,
    "composite": true,
    "incremental": true
  },
}

🙁 Actual behavior

Running tsc -b -w is much slower (total time 4.20s) than tsc -p -w (total time 0.11s). The library that seems to be slowing it down is aws-sdk package which is the only dependency in this small repro project.

Why would the same package be parsed much slower in the build mode?

🙂 Expected behavior

Compilation time after adding a change (eg console.log in the TS file) should be nearly the same between tsc -b -w and tsc -p -w when there are no project references specified.

[andrewbranch]

Duplicate of #45082

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.