Make errors for using advanced JS features friendlier

[MrMagma]

This pull request fixes #492 by editing the jshint messages for using ES7 and ES6 features to be worded in a more friendly and helpful way.

Minor Changes

external/jshint/jshint.js

• Switch W104 from "'some feature' is only available in JavaScript 1.7." to "It looks like you're trying to use 'some feature'. 'some feature' is a JavaScript 1.7 feature and is not currently supported in the live editor."
• Switch W109 from "'some feature' is only available in ES6 (use esnext option)." to "'some feature' is only available in ES6 which is not supported by the live editor at this point."

If any editing is required please let me know.

Thank you for your time.

[pamelafox]

Can you change "live editor" to "this editor" or "this environment"?

[MrMagma]

Will do!

[MrMagma]

@pamelafox I've made the edit you suggested. Let me know if there's anything else I should do.

[pamelafox]

Change to environment

[MrMagma]

Oops. Sorry bout that. I do not have access to my desktop currently but once I do I'll fix this and let you know. Sorry for the goof-up.

[GoToLoop]

I did some looking around and let, const, and destructuring assignments are all 1.7 features, ...

• Actually all of them are ES6 a.K.a ES2015.
• And const was picked up so early by ES5 browsers that it should be considered ES5 in practice:
  https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const
• let took a lot more though. And in order to use it, it demands 'use strict';:
  https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let
• ES7 instead is gonna bring us very advanced stuff like SIMD:
  https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SIMD

IMO, Khan shouldn't bar ES6 features at all. Specially something as old as const!

[kevinbarabash]

IMO, Khan shouldn't bar ES6 features at all. Specially something as old as const!

It's not a question of barring ES6 features, it's a question of supporting them. We want all CS programs to run cross browser which means that we'd have to babel to compile them. We'd also have to update the linter (or switch to eslint if we want to support all ES6).

[GoToLoop]

We want all CS programs to run cross browser which means that we'd have to babel to compile them.

• That all depends on establishing the minimum browser version where full support is guaranteed.
• Keyword const for example is recognized on very old browsers like Opera 12 and no need for Babel.
• However, while IE11 works, IE10 doesn't recognize const.
• But IE browser is gonna be defunct soon and be replaced by Edge for those who prefer MS.
• It's a pity to bar folks to enjoy some ES6 features when it's already available in modern browsers.
• And btW, I bet classes gonna bring lotsa Java, C#, Python, etc. programmers to JS camp! :D
  https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes

[MrMagma]

@pamelafox Sorry for that goof-up I've fixed it now and everything should be ready. Very sorry for that.

[kevinbarabash]

However, while IE11 works, IE10 doesn't recognize const.

While we're dropping IE9 support as of Jan 2016, we'll still be support IE10 for a while.

I bet classes gonna bring lotsa Java, C#, Python, etc. programmers to JS camp! :D

They also make using classes less intimidating for beginner programmers.

[kevinbarabash]

@JavaScriptFTW instead of merging master can you rebase your changes on to master?

[MrMagma]

@kevinbarabash It's rebased now. It should be ready for merging once the tests are complete.

[MrMagma]

@kevinbarabash I believe that I've changed the message according to your suggestion.

[kevinbarabash]

Excellent. LGTM.

[kevinbarabash]

@JavaScriptFTW thanks for the pull request.

[GoToLoop]

While we're dropping IE9 support as of Jan 2016, we'll still be support IE10 for a while.

Seems like not even MS wants to support those very old browsers anymore after January 12, 2016: :-D
https://www.Microsoft.com/en-us/WindowsForBusiness/End-of-IE-support

For now IE11 survives. But I bet it's not gonna take too long for MS to support Edge only... @_@