Can I use
?

WebAssembly BigInt to i64 conversion in JS API

- WD

An extension to the WebAssembly JS API for bidrectionally converting BigInts and 64-bit WebAssembly integer values

Chrome

  1. ❌ 4 - 84: Not supported
  2. ✅ 85 - 130: Supported
  3. ✅ 131: Supported
  4. ✅ 132 - 134: Supported

Edge

  1. ❌ 12 - 84: Not supported
  2. ✅ 85 - 130: Supported
  3. ✅ 131: Supported

Safari

  1. ❌ 3.1 - 14: Not supported
  2. ✅ 14.1 - 18.0: Supported
  3. ✅ 18.1: Supported
  4. ✅ 18.2 - TP: Supported

Firefox

  1. ❌ 2 - 77: Not supported
  2. ✅ 78 - 131: Supported
  3. ✅ 132: Supported
  4. ✅ 133 - 135: Supported

Opera

  1. ❌ 9 - 70: Not supported
  2. ✅ 71 - 113: Supported
  3. ✅ 114: Supported

IE

  1. ❌ 5.5 - 10: Not supported
  2. ❌ 11: Not supported

Chrome for Android

  1. ✅ 131: Supported

Safari on iOS

  1. ❌ 3.2 - 14.4: Not supported
  2. ✅ 14.5 - 18.0: Supported
  3. ✅ 18.1: Supported
  4. ✅ 18.2: Supported

Samsung Internet

  1. ❌ 4 - 13.0: Not supported
  2. ✅ 14.0 - 25: Supported
  3. ✅ 26: Supported

Opera Mini

  1. ❌ all: Not supported

Opera Mobile

  1. ❌ 10 - 12.1: Not supported
  2. ✅ 80: Supported

UC Browser for Android

  1. ✅ 15.5: Supported

Android Browser

  1. ❌ 2.1 - 4.4.4: Not supported
  2. ✅ 131: Supported

Firefox for Android

  1. ✅ 132: Supported

QQ Browser

  1. ﹖ 14.9: Support unknown

Baidu Browser

  1. ﹖ 13.52: Support unknown

KaiOS Browser

  1. ❌ 2.5: Not supported
  2. ﹖ 3: Support unknown

Safari supported BigInt in version 14.1, but did not support BigInt64Array (which is also required for Emscripten's BigInt support) until version 15

Resources:
Feature extension overview