How old and how backward compatible are you thinking?
- Symbol is 2014-2015
- Map is 2014-2015
- Weak* data structures and their methods span 2014-2021
- WebGL 2.0 is 2017-2021
- Custom Elements are 2017-2021
- Chrome-only non-standards (hardware APIs and a bunch of others) are pumped out at a rate of up to 400 per year
- WebAssembly MVP is 2017-2018
And so on. That's off the top of my head. None of them are backwards compatible. Some of them cannot be polyfilled.
How old and how backward compatible are you thinking?
- Symbol is 2014-2015
- Map is 2014-2015
- Weak* data structures and their methods span 2014-2021
- WebGL 2.0 is 2017-2021
- Custom Elements are 2017-2021
- Chrome-only non-standards (hardware APIs and a bunch of others) are pumped out at a rate of up to 400 per year
- WebAssembly MVP is 2017-2018
And so on. That's off the top of my head. None of them are backwards compatible. Some of them cannot be polyfilled.