Transpile dependencies of the test file

[madbence]

ava@0.3 works smoothly on a clean project, but fails to run on mine (tests broke when i've upgraded to from ava@0.2):

(function (exports, require, module, __filename, __dirname) { import {
                                                              ^^^^^^
SyntaxError: Unexpected reserved word

I'm sure it's caused by some weird babel dependency, so it might be unrelated to ava. Last working state is 7d31571, if i try to upgrade to ava@0.3, tests are broken.
I will investigate it tomorrow...

[Qix-]

Did you try rm -rf node_modules and npm i?

What version of Node are you using? Something tells me Babel was removed from compiling tests.

[madbence]

yup, still the same, btw it might be the same as #108 ?

[Qix-]

Yep, that's my guess.

[madbence]

So right now there is no way to test modules directly? I mean, i have to transpile them first, and test the transpiled files?

[sindresorhus]

Implicitly transpiling dependencies in 0.2.0 was a bug that was later fixed 0.3.0. Transpiling dependencies by default is both surprising and slow. I'm open to considering an option for enabling this, but it will not be by default.

[madbence]

what about allowing something like $ babel-node node_modules/.bin/ava ? i'm not really familiar with ava internals, so that's just an idea.

[sindresorhus]

That won't work as we spawn the test files. Just use AVA 0.2.0 until we've figured out how to deal with this. Alternatively use a fork where you've removed this line.

[axross]

I'm open to considering an option for enabling this, but it will not be by default.

I agree. I want to run both tests and target codes for tests with Babel. I think that is proper and as it should be.

[sindresorhus]

What should the option be named?

[sindresorhus]

@floatdrop Any thoughts as to how we should solve this now that #103 has landed?

[floatdrop]

@madbence you can require file with following code in tests as workaround:

// app.es5.js
require('babel/register');
require('./app');

@sindresorhus besides this workaround, not really.

[sindresorhus]

We could set the execPath, when we fork a test file, to the babel-node executable instead of vanilla node.

[imevro]

Hm, any progress on that? Still can't use external files.

[sindresorhus]

@theaqua This issue is still open, so no. @floatdrop has already provided a workaround if you can't wait.

To move this issue forward, come up with a good name for a CLI flag to enable it.

[imevro]

pm2 uses execInterpreter option. I think it's ok because most users will install custom interpreter (coffeescript or babel) as dependency and ava can search in local node_modules automagically.

[bookercodes]

@theaqua If I understand correctly, that is what Mocha does too.

[madbence]

@sindresorhus

• --transpile-all|-a
• --compile-all|-a
• or to be more flexible, do something like --compilers js:babel/register (like in mocha, istanbul, etc)

[bookercodes]

@madbence I like --transpile-all.

I think --transpile-transitive is more descriptive/accurate, though.

Then again, "transpile" a general term. As AVA specifically transpiles using Babel, maybe "babelify" would be a better word.

[Qix-]

--transpile-transitive would be the longest command line flag I've seen in a while.

[bookercodes]

@Qix- -tt for short

[Qix-]

Per GNU specs on arguments, -tt would be supplying the short-form argument -t twice. Doesn't make sense. --transpile-all would make the most sense whilst still being correct. --compile-all isn't technically correct but would still probably be easier for people to type.

[madbence]

btw what's the rationale behind this behavior (ava transpiles tests only)? it's just slow?

[bookercodes]

@madbence #50

[jamestalmage]

It is more than just "ava transpiles tests only".

It is that ava allows you to write tests in ES2015 with zero impact on your production environment.
By zero impact, I mean no transpilation an no polyfills. (IMO polyfills are the sneakier harder to detect bug).

For example, we make sure Promise is available inside your tests, without impacting it's availability in production code.

// Always works in tests. Only works in production in Node >= 0.12
new Promise(...)

Trickier still is a prototype polyfill. Something like String.prototype.includes(). If Babel actually modifies the prototype, your test suite no longer protects you against mistakenly using str.includes() in production. Users will report errors in Node 0.12 that you can't write a failing test case for (because it has been polyfilled even in your production environment).

AVA uses the runtime plugin to provide polyfill aliasing. An example of how that works is here. This means that:

".... some string ....".includes()

Will work in your tests on any platform. But will throw in production code on platforms that do not support str.includes()

[billyjanitsch]

+1 for a --compilers (or perhaps --preprocessors) flag that lets you use custom register hooks, like mocha does (as @alexbooker alluded to) with a pretty clean syntax. Other test runners (Karma, babel-tape-runner) do similar things.

Including import babel-core/register at the top of every test file is clunky enough, and gets much worse if you want to write a custom compiler (e.g. like this, which is necessary to test JS that uses CSS modules). You should be able to specify this when invoking AVA.

[sparty02]

import babel-core/register is a really good, simple workaround until this feature lands. @sindresorhus what do you think about putting this in the README until it's officially addressed? (I wouldn't mind submitting a PR for it)

[sindresorhus]

@sparty02 Sure, PR welcome.

[franleplant]

Hi!
import 'babel-core/register' and import 'babel-register' are not working for me.

[jamestalmage]

You need to install as dependencies of your own project to use outside of tests

[franleplant]

Already done that @jamestalmage

[franleplant]

It was purely a problem with babel presets/plugins/config settings, nvm, thanks a lot

[ariporad]

EDIT: Whoops... Not the issue I thought it was. Sorry!

[franleplant]

:)

[Hurtak]

for anybody trying to make import 'babel-core/register'; work in AVA, try installing babel-core 5.x.x, that did the trick for me, 6 doesn't work for some reason (you probably need have properly configured .babelrc in your directory or something)

[ariporad]

@Hurtak: Yes. Babel 6 doesn't do anything by default.

[kentcdodds]

This issue is solved for me by adding --require 'babel-register' (Babel 6) with a .babelrc file:

{
  "presets": ["es2015", "stage-2"]
}

[kentcdodds]

If you're interested, here's a migration from Mocha to AVA in a small library: https://github.com/kentcdodds/starwars-names/pull/12/files?w=1

edit the reason I bring it up is because it supports ES6 with Babel 6 in my source without having to import babel-register. Thought you'd all be interested.

[jamestalmage]

Cool!

Your use of the --require flag is spot on for what we intended. #407 should make the experience even better.

We would value any feedback on pain points you encountered during the transition.

[kentcdodds]

Cool, I added a comment about that. I prefer to use config to avoid polluting the package.json keyspace :-) (It's also technically the recommended way to do what is being done).

Not really any pain points. The only thing that I would say is the assertions are pretty limiting. I prefer the declarative syntax of something like Chai. But I expect that the small surface area of the API is intentional. I ended up bringing in another utility library to make testing a little more declarative though.

[azhang]

This is what I use in my package.json file:

  "scripts": {
    "test": "ava --require babel-register --require babel-polyfill '**/*.test.js'"
  },
  "dependencies": {
    "babel-core": "^6.4.0",
    "babel-polyfill": "^6.3.14",
    "babel-preset-es2015": "^6.3.13",
    "babel-preset-stage-0": "^6.3.13",
    "babel-register": "^6.3.13"
  },
  "devDependencies": {
    "ava": "^0.9.2"
  },
  "babel": {
    "presets": [
      "es2015",
      "stage-0"
    ],
  },

[ruyadorno]

Had to dig around this issue this morning to get it working with babel@6.5.2 in order to run on travis with node@0.12.10 and npm@2.14.9

I had to use the ignore babel config property that somehow went unmentioned in this whole thread, here is the actual snippet of code that I dropped at the top of my test file:

require('babel-core/register')({
    ignore: false
});

TIP: ignore can also be a function that receives a filename and returns false, this way you can filter only the files that need the transpiling, I ended up using it and test times were a lot better

[novemberborn]

@sindresorhus @vdemedes @jamestalmage is there anything we want to improve here beyond the existing --require support? If not I'll close and remove the link to this issue from the README.

[sindresorhus]

Not that I'm aware of.

[vadimdemedes]

Sure, we can close it for now.

[z-vr]

@Whoaa512 dude you rule