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ts-browser-compat

Check TypeScript projects for browser compatibility, using MDN browser-compat-data - the same data that powers caniuse.com.

Important note: This uses heuristics to report usage of APIs that may not be supported. The heuristics are not accurate in all cases - manually check the results.

Simple Usage

npx @journeyapps/ts-browser-compat -b firefox:55 -b safari_ios:13

Sample output:

AbortController - firefox 57, safari_ios 12.2
  src/client.ts:196
AbortController.abort - firefox 57, safari_ios 12.2
  src/client.ts:210
AbortController.signal - firefox 57, safari_ios 12.2
  src/client.ts:202
Blob.arrayBuffer - firefox 69, safari_ios 14
  src/convert.ts:64
Blob.text - firefox 69, safari_ios 14
  src/convert.ts:87
  src/convert.ts:93

Limitations

This project works by cross-referencing type references from DOM and built-in libraries in TypeScript, to the MDN browser compatibility data.

  • No support for checking CSS.
  • No support for checking HTML.
  • No support for checking DOM events.
  • Does not check for supported JavaScript syntax. Use target in tsconfig.json for this.
  • Limited support for checking JavaScript source files: It only works as well as the TypeScript compiler can infer the types.
  • Unpredictable results when a browser lists partial support for an API.
  • Potential for inaccuracies with mapping the TypeScript definition to the compatibility data.
  • Does not automatically build or check referenced projects.
  • Does not check implementation of dependencies with type declarations.
  • Does not detect safe API usage using guard statements.

Usage in a project

For regular use, add as a dependency:

npm install --save-dev @journeyapps/ts-browser-compat

Then create a ts-browser-compat.json config file:

{
  // List of minimum browser versions
  "browsers": {
    "firefox": "55",
    "safari_ios": "13"
  },
  // Optional path to TypeScript projects - defaults to current dir
  "path": ["src", "web"],
  //
  "polyfills": [
    // Mark a specific property or method as implemented
    "Promise.finally",
    // This only matches the contructor, no properties or methods
    "AbortController",
    // This matches the constructor and all properties and methods
    "Blob.*"
  ],
  "ignore": [
    // Same as polyfills. Use this to indicate that the code handles missing APIs in a way other than polyfilling.
  ],
  // By default, TypeScript's type checker is run, to ensure that TypeScript errors don't prevent these checks from working.
  // It can be disabled to speed up the checks.
  "skipTypeCheck": true
}

To ignore a single API usage, add // @tsbc-ignore on the previous line. If an API is used in many places, wrap it in an internal module, or add it to the polyfills or ignore lists.