Swap isparta for babel-plugin-istanbul

[jamesplease]

isparta isn't maintained, and it seems that the latest istanbuls might have better support for ES2015+.

[paulfalgout]

FWIW I successfully made the switch to gulp-babel-istanbul on one project after having an isparta issue.

[paulfalgout]

here's a specific example. Pretty easy switch. RoundingWellOS/marionette.toolkit@55993bd

[jamesplease]

Nice!

[jamesplease]

Note that this swaps isparta for https://github.com/jmcriffey/babel-istanbul, another library that is a "temporary fix." Eventually we will want to use just vanilla istanbul.

It might be worth using istanbul alpha for reasons like jeffrifwald/babel-istanbul#56 (comment)

[jamesplease]

My approach here will be to test babel-istanbul against istanbul beta on some project of mine. If istanbul beta is up to snuff, I'll use that. Otherwise, I'll switch to babel-istanbul.

[jamesplease]

Ah jeez, yet another option: https://github.com/dtinth/babel-plugin-__coverage__

Coverage + transpiled code is in a rough place right now. That last one looks like it might be promising, but I'll have to investigate further...

[jamesplease]

more: istanbuljs-archived-repos/istanbul-lib-instrument#4

[jamesplease]

Looks like the babel-plugin-__coverage__ tool is working well for people. And now that it's been out for some time, so I think that'll be what I transition to.

[hzoo]

There's also https://github.com/istanbuljs/babel-plugin-istanbul now (based off of ^)

[jamesplease]

Ha I was literally just posting that @hzoo! Thanks for the link ;)

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In this comment it's mentioned that babel-plugin-istanbul might be significantly slower than __coverage__. I'll have to check to see if they've improved the performance at all, or if the slow performance seems like a problem.

[hzoo]

Ah I might have some answers for that - https://github.com/babel/babel/releases/tag/v6.11.3 Ref istanbuljs/babel-plugin-istanbul#5 - logan made some generator improvements but yeah I would check to confirm

[jamesplease]

Alright – after some investigating I'm confident that switching to babel-plugin-istanbul is a good move forward.

[bcoe]

@jmeas @hzoo let me know if you run into any issues, happy to land patches 👍

@hzoo also, reminds me, I owe you adding babel-plugin-istanbul to babel's own tests!

[hzoo]

@bcoe We have it for babylon at least now https://github.com/babel/babylon/blob/master/.babelrc#L6