Infinite loop when using grunt watch with babel require hook

[sethpollack]

Im trying to use the Babel require hook in my Gruntfile. Everything works fine until I try to use grunt-watch.

Here is an example.

module.exports = function(grunt) {

  require('babel/register')({
    experimental: true,
    extensions: ['.es6'],
  });

  require('load-grunt-tasks')(grunt);

  grunt.initConfig({
    mochaTest: {
      options: {
        reporter: 'spec'
      },
      src: ['test/**/*.es6'],
    },
    watch: {
      files: ['lib/**/*.es6'],
      tasks: ['test']
    }
  });

  grunt.registerTask('test', ['mochaTest']);

};

First a get a bunch of these messages

Running "watch" task
Waiting...
Warning: boolean is not a function

Followed by a bunch of these...

(node) warning: Recursive process.nextTick detected. This will break in the next version of node. Please use setImmediate for recursive deferral.

and then

RangeError: Maximum call stack size exceeded

[vladikoff]

@shama example project https://github.com/vladikoff/grunt-watch-issue-babel425

Not seeing what causing this yet...

[vladikoff]

Adding

  require('babel/register')({
    experimental: true,
    extensions: ['.es6'],
  });

breaks things...

[shama]

What happens when you enable stack? grunt watch --stack and remove mochaTest from the equation.

node-inspector is a great tool for debugging these things.

[shama]

My guess is it's from tiny-lr and specifically this: https://github.com/jshttp/on-finished/blob/master/index.js#L65

FWIW, this kind of bad stuff happens when you globally apply an es6 library. Why not just use babel when you need it instead of applying it everywhere?

[tikotzky]

the babel require hook above actually will only touch .es6 files Thats what extensions: ['.es6'] is setting.

So babel shouldn't be touching anything from tiny-lr

[tikotzky]

FWIW moving the require('babel/register') to the end of the file seems to work. This does kinda indicate that its babel doing something wrong.

module.exports = function(grunt) {

  require('load-grunt-tasks')(grunt);

  grunt.initConfig({
    mochaTest: {
      options: {
        reporter: 'spec'
      },
      src: ['test/**/*.es6'],
    },
    watch: {
      files: ['lib/**/*.es6'],
      tasks: ['test']
    }
  });

  grunt.registerTask('test', ['mochaTest']);

  require('babel/register')({
    experimental: true,
    extensions: ['.es6']
  });

};

[sethpollack]

Nice! Thanks!

[shama]

Thanks @tikotzky. That is very strange though, I'm curious to know where it's getting tripped up.