Add Babel

[hzoo]

Ref #9

Just add's Babel, but with preset-env

Old description

- add `make build` and `npm run build` - rename src files to `src` instead of `lib`

Just did the basic thing, probably needs changes, might need to look again monday/tues though since I'm busy for most of tomorrow.

These tests were failing for me locally for some reason (node 6) on master as well

  gyppies
    1) should build copies
    2) should build executable
    3) should build loadable_module
    4) should build shared_lib
    5) should build static_lib

     Error: spawnSync ninja ENOENT
      at exports._errnoException (util.js:1007:11)
      at spawnSync (child_process.js:464:20)
      at Context.it (test/gyppies-test.js:28:9)

[hzoo]

Not compiling bin/ and since its just a few lines I just changed to var

[indutny]

👍

[indutny]

Thank you! Tests require ninja binary in a PATH. It could be installed from https://ninja-build.org/ or built from source.

[hzoo]

Cool just did brew install ninja and it's good. Actually found a bug with babel haha regarding const/scoping, which I reduced to

function Ninja() {}
Ninja.prototype.copies = function copies() { // SyntaxError: "copies" is read-only
  const copies = 1; // 
};

Ok odd it's getting Error: Cannot find module '../lib/gyp/generator/ninja/writer' on CI (works locally now)

Need to add transform-runtime for Map etc

[indutny]

Thank you so much for this!

I'm a complete noob with regards to Babel. As far as I got it, it looks like require('gyp.js') will always work with a transpiled version. Is this correct? Wouldn't it be slower than what we currently have?

Unfortunately there are no benchmarks for the input at the moment, so I guess it could be benchmarked only on node.gyp.

[kzc]

Wouldn't it be slower than what we currently have?

Idiomatic ES6 is typically slower than hand-written ES5 on v8 as it is not as well tuned.

https://kpdecker.github.io/six-speed/
http://www.incaseofstairs.com/2015/06/es6-feature-performance/
https://news.ycombinator.com/item?id=11203183

for/of loops, for example, should be avoided.

[indutny]

@kzc so basically, the things that I have used here are: const/let, arrow functions, and some String# methods.

[indutny]

@hzoo I have simplified lots of code in recent commits. I think we now use only let and const from ES6. Should be much simpler for a Babel now 😉

[hzoo]

Adding more or less ES6 is fine for Babel 😄 (given i'm running the es2015 preset which transpiles es6 syntax, otherwise could choose a smaller/specific set of transforms). Still have to transpile the use of stuff like Map/Set though (either a specific module like es6-map or use the babel one (core-js))

[indutny]

@hzoo yeah, I just hope to gain as much control as possible over the resulting code. Optimally, it should be almost the same, but with let/const replaced by vars and => replaced by functions. This way, we can have some kind of expectations of resulting performance.

[hzoo]

You can use "loose" mode for most things but ok, what do you want to do for Map/Set? There's http://babeljs.io/docs/plugins/transform-runtime/ (uses https://github.com/zloirock/core-js) or another polyfill

[indutny]

@hzoo I think loose mode is what we actually need indeed. I have no idea what polyfills are best, its up to you! 👍

[hzoo]

Sorry didn't get to update this. When I rebased, I realize that parser-base doesn't work on node 0.10 either 😛 (Can either run babel on that too.. or just paste that code in the babel repl and replace)

Also do we want a polyfill that changes globals (Map, Set) or just use the ponyfill's modules?

edit: Not sure why the commits aren't updating. branch is here: https://github.com/hzoo/gyp.js/tree/add-babel (can do another pr)

[hzoo]

yeah, I just hope to gain as much control as possible over the resulting code.

Also regarding your earlier comment, babel is pretty good on the output of most things (especially with loose mode). Like classes is no big deal (you can try it in the repl here). In that case, the only thing it adds that you wouldn't do handwritten is the classCallCheck to make sure you call with new. Basically destructuring is essentially the same too

so let/const, template strings, destructuring, classes, arrow functions, shorthand methods/properties, computed properties, literals are simple.

[hzoo]

@indutny should I still update this? Not sure why the commits are off now (maybe force pushed incorrectly)

[indutny]

@hzoo TBH, I'm not yet sure. I think that I have reduced ES6 usage to get this thing working on node.js v4-master.

At the moment, @pmed is pushing gyp.js as a backend for node-gyp, and I would like to keep this a priority for this project.

I'm really glad to see lots of things that you did here. Let's return to this a bit later, when we will reach the node-gyp goal.

Thanks!

[hzoo]

Ok rebased again so it only has my changes. it fails on node 0.10 because some of the dependencies are on node 4

[hzoo]

@indutny should I close this PR? It's been a long time but it's a lot easier to do this now with babel-preset-env, by targeting node 0.10/0.12/4/etc (it only compiles what's not supported)

{
  "presets": [
    ["env", {
      "targets": {
        "node": 4
      }
    }]
  ]
}

[indutny]

Actually, I have been playing with babel lately and I think I'm finally ready to accept this 👍

Would you care to rebase this PR, please?

[hzoo]

Ok I rebased and am targeting node 4 (since now 0.10/0.12 are deprecated) if that is what we wanted now

[indutny]

Landed in 1ad257b, thank you so much! This should give me some starting base to porting this to duktape.

[hzoo]

Do we close #9 now?

[indutny]

Yes! https://github.com/indutny/dukgyp