Can I use
?

let

- OTHER

Declares a variable with block level scope

Chrome

  1. ❌ 4 - 18: Not supported
  2. ❌ 19 - 40: Disabled by default
  3. ◐ 41 - 48: Partial support
  4. ✅ 49 - 148: Supported
  5. ✅ 149: Supported
  6. ✅ 150 - 152: Supported

Edge

  1. ✅ 12 - 148: Supported
  2. ✅ 149: Supported

Safari

  1. ❌ 3.1 - 9.1: Not supported
  2. ◐ 10 - 10.1: Partial support
  3. ✅ 11 - 26.3: Supported
  4. ✅ 26.4: Supported
  5. ✅ 26.5 - TP: Supported

Firefox

  1. ❌ 2 - 43: Disabled by default
  2. ✅ 44 - 150: Supported
  3. ✅ 151: Supported
  4. ✅ 152 - 154: Supported

Opera

  1. ❌ 9 - 12.1: Not supported
  2. ❌ 15 - 27: Disabled by default
  3. ◐ 28 - 35: Partial support
  4. ✅ 36 - 127: Supported
  5. ✅ 131: Supported

IE

  1. ❌ 5.5 - 10: Not supported
  2. ◐ 11: Partial support

Chrome for Android

  1. ✅ 149: Supported

Safari on iOS

  1. ❌ 3.2 - 9.3: Not supported
  2. ◐ 10 - 10.3: Partial support
  3. ✅ 11 - 26.3: Supported
  4. ✅ 26.4: Supported
  5. ✅ 26.5: Supported

Samsung Internet

  1. ◐ 4: Partial support
  2. ✅ 5 - 29: Supported
  3. ✅ 30: 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. ✅ 149: Supported

Firefox for Android

  1. ✅ 151: Supported

QQ Browser

  1. ✅ 14.9: Supported

Baidu Browser

  1. ✅ 13.52: Supported

KaiOS Browser

  1. ✅ 2.5: Supported
  2. ✅ 3: Supported
Resources:
MDN Web Docs - let
Variables and Constants in ES6