Parallel Transpile

This npm module uses webpack loaders and all your CPUs to transpile source as quick as it can.

Installation

npm install -g parallel-transpile

Also install any webpack loaders you require, e.g.

npm install -g cjsx-loader coffee-loader jsx-loader json-loader

Usage

Usage: parallel-transpile [options] -o outputDirectory inputDirectory

  -h, --help          display this help message
  -v, --version       output version number
  -w, --watch         watch input directories for changes
  -o, --output        the output directory
  -p, --parallel      how many instances to run in parallel
                        (defaults to number of CPUs)
  -t, --type          add a type to be converted, see below
                        (can be called multiple times)
  -n, --newer         only build files newer than destination files

Types

  Each type takes an input filter (file extension), a list of loaders, and
  an output extension. To copy a file verbatim, only the input filter is
  required.

  For example, to copy all JSON files verbatim:

    -t ".json"

  To compile a CJSX file to JavaScript:

    -t ".cjsx:coffee-loader,cjsx-loader:.js"

  Loaders operate from right to left, like in webpack.

Example

The following example recurses through the src folder, converting all .cjsx, .coffee and .litcoffee files to .js and copying all .js and .json files verbatim into the build directory. It also watches for changes in src (including additions), updating the build directory as required.

parallel-transpile \
  -o build \
  -w \
  -t .cjsx:jsx-loader,coffee-loader,cjsx-loader:.js \
  -t .coffee:coffee-loader:.js \
  -t .litcoffee:coffee-loader?literate:.js \
  -t .json \
  -t .js \
  src

Usage as a module

You can also use parallel-transpile as a module, which can be useful e.g. in grunt. For a simple parallel build you might do something like:

var parallelTranspile = require('parallel-transpile');

grunt.registerTask("parallel-transpile", function() {
  var done = this.async();
  var options = {
    output: "build",
    source: "src",

    type: [
      ".cjsx:jsx-loader,coffee-loader,cjsx-loader:.js",
      ".coffee:coffee-loader:.js",
      ".litcoffee:coffee-loader?literate:.js",
      ".json",
      ".js"
    ]
  };

  parallelTranspile(options, done);
});

The real power comes when you combine this with watching for changes. You can have your grunt task wait for the initial build to complete before moving on to the next grunt task but continue watching for changes in the background, like this:

var parallelTranspile = require('parallel-transpile');

grunt.registerTask("parallel-transpile:watch", function() {
  var done = this.async();
  var options = {
    output: "build",
    source: "src",

    type: [
      ".cjsx:jsx-loader,coffee-loader,cjsx-loader:.js",
      ".coffee:coffee-loader:.js",
      ".litcoffee:coffee-loader?literate:.js",
      ".json",
      ".js"
    ],

    watch: true,
    initialBuildComplete: done
  };

  parallelTranspile(options, function() {
    console.error("Parallel-transpile exited");
  });
});

License

MIT