Can I use
?

Object.observe data binding

- UNOFF

Method for data binding, a now-withdrawn ECMAScript 7 proposal

IE

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

Edge

  1. 12 - 86: Not supported
  2. 87: Not supported

Firefox

  1. 2 - 83: Not supported
  2. 84: Not supported
  3. 85 - 86: Not supported

Chrome

  1. 4 - 35: Not supported
  2. 36 - 49: Supported
  3. 50 - 86: Not supported
  4. 87: Not supported
  5. 88 - 90: Not supported

Safari

  1. 3.1 - 13.1: Not supported
  2. 14: Not supported
  3. TP: Not supported

Opera

  1. 9 - 22: Not supported
  2. 23 - 36: Supported
  3. 37 - 71: Not supported
  4. 72: Not supported

iOS Safari

  1. 3.2 - 13.7: Not supported
  2. 14: Not supported

Opera Mini

  1. all: Not supported

Android Browser

  1. 2.1 - 4.4.4: Not supported
  2. 81: Not supported

Opera Mobile

  1. 10 - 12.1: Not supported
  2. 59: Not supported

Chrome for Android

  1. 87: Not supported

Firefox for Android

  1. 83: Not supported

UC Browser for Android

  1. 12.12: Not supported

Samsung Internet

  1. 4: Supported
  2. 5 - 12.0: Not supported
  3. 13.0: Not supported

QQ Browser

  1. 10.4: Not supported

Baidu Browser

  1. 7.12: Supported

KaiOS Browser

  1. 2.5: Not supported

Support in Blink-based browsers is expected to be removed in future versions.

Resources:
Firefox tracking bug
An update on Object.observe
Polyfill
Data-binding Revolutions with Object.observe()