A build tool for Node.js
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A build tool for Node.js programs.


Install globally with

npm install -g treadmill

Or add to your local dependencies in package.json with

npm install --save treadmill


Say you have a project folder that looks something like this:

├── frontend
│   └── scripts
│   |   ├── main.js
│   |   └── store.js
|   └── styles
│       ├── main.scss
│       └── buttons.scss
├── public
│   └── assets
└── server
    └── server.js

You could write an asset build file for Treadmill in the root of your project as build.js like this:

'use strict';

const treadmill = require('treadmill');
const browserify = require('browserify');
const sass = require('sass');

const task = treadmill.task;
const Promise = treadmill.Promise;
const log = treadmill.log;

task('bundle-js', function (args, done) {
  const cwd = args.get('currentWorkingDirectory');
  const src = cwd.append('frontend', 'scripts', 'main.js');

  const bundler = browserify({
    debug: true,
    entries: [src]

  return bundler.bundle().on('error', done);

task('bundle-sass', function (args, done) {
  const src = args.cwd.append('frontend', 'scripts', 'main.js');

  const options = {
    file: src.toString(),
    outputStyle: 'compact'

  sass.render(options, done);

task('build-assets', ['bundle-js', 'bundle-sass'], function (args) {
  const cwd = args.get('currentWorkingDirectory');
  const jsDest = cwd.append('public', 'assets', 'scripts', 'main.js');
  const cssDest = cwd.append('public', 'assets', 'styles', 'main.css');

  return Promise.all([
    jsDest.write(args.get('bundle-js')).then(function (file) {
      log('JavaScript bundle %d', file.stats().size);
    cssDest.write(args.get('bundle-sass')).then(function (file) {
      log('CSS bundle %d', file.stats().size);

And run it like this:

treadmill build.js build-assets

Creating Tasks

Use the task() function like in the example above to create tasks. task() takes 3 parameters:

  • name - String name of the task (will be used in arguments to Handler Function later; see below). required
  • dependencies - Array of names of tasks which should automatically be run first. optional
  • handler - The handler Function (see Handler Function below). required

The listed dependency tasks will be run first and the results passed into your handler (see Handler Function below).

Handler Function

Your Handler Function will be passed 2 arguments:

  • args - An Immutable.Map of the results from your dependencies as well as a few helpful defaults (see Handler Arguments below).
  • done - A callback Function to signal the task is complete.

Handler - args

The first argument passed to your handler is called args and it is an Immutable.Map of some useful default values as well as the results of all your dependencies. Since args is an Immutable Object you'll need to get values from it using the getter like this:

const cwd = args.get('currentWorkingDirectory');

Handler - args defaults

  • currentWorkingDirectory A Filepath Object representing the current working directory.

Example using args

task('build-something', ['collect-files'], args => {
  // The results of dependency tasks are collected into the args
  // Immutable.Map for you.
  const files = args.get('collect-files');

  // Available by default
  const cwd = args.get('currentWorkingDirectory');

  return buildSomethingAsync(cwd, files);

Handler - done

If you accept the done argument like this:

task('build-something', (args, done) => {

Your task will not complete until done() is called. If you pass an argument to done() Treadmill will assume it is an error and report it as such. This is a Node.js convention.

Treadmill Knows Promises! If you do not accept the done argument in your handler like this:

task('build-something', (args) => {
  return buildSomethingAsync().then(result => {
    return compressSomething(result);

Treadmill will assume that you returned a Promise from your Handler and will report the resolve or reject from that promise.

Copyright and License

Copyright (c) 2013 - 2016 by Kris Walker kris@kixx.name (http://www.kixx.name).

Unless otherwise indicated, all source code is licensed under the MIT license. See MIT-LICENSE for details.