[Documentation] JavaScript Environment Requirements

[EWhite613]

📙 Describe the Issue

With the new Ember browser support policy it's difficult to see a way forward with Ember for apps that need to support legacy browser versions outside that statement.

Ember should have a JavaScript Environment Requirements like React did, and other libraries have. And include in changelogs when new features are used (react example).

This way those that need to support older legacy browser versions at least have an idea what they need to polyfill (or if they can even polyfill).

[MelSumner]

This is a great idea, do you want to share what you've learned or have run into so far?

[MelSumner]

cc @emberjs/learning-core this might be a good issue for learning?

[jenweber]

Thanks for flagging this! It is a good issue for the website project, since that's where the page https://emberjs.com/browser-support/ lives and where we would ultimately put this content. So, I copied it over and I'm closing the issue for this repository. If anyone wants to work on it, please continue in ember-learn/ember-website#1036. I added a to-do list. Thank you!

[EWhite613]

Thanks @MelSumner @jenweber

This is a great idea, do you want to share what you've learned or have run into so far?

@MelSumner for me it's essentially Ember's new browser support statement (introduced in v4) blocks me from upgrading (we need to support older browsers outside of the statement). And atm w/o "JavaScript Environment Requirements" it's difficult to determine if there's a viable path forward with Ember for us. I believe from code I've seen it would work for us but I'd only really upgrade with a concrete list of what would need to polyfil/runtime requirements, as it's too risky/expensive operation otherwise.