npm: gulp

gulp

4.0.0 • Public • Published a year ago

The streaming build system

What is gulp?

Automation - gulp is a toolkit that helps you automate painful or time-consuming tasks in your development workflow.
Platform-agnostic - Integrations are built into all major IDEs and people are using gulp with PHP, .NET, Node.js, Java, and other platforms.
Strong Ecosystem - Use npm modules to do anything you want + over 2000 curated plugins for streaming file transformations
Simple - By providing only a minimal API surface, gulp is easy to learn and simple to use

Installation

There are a few ways to install:

gulp v4.0.0 - npm install gulp@next
gulp v4.0.0-alpha.3 - npm install gulpjs/gulp#v4.0.0-alpha.3
gulp v3.9.1 - npm install gulp

Documentation

For a Getting started guide, API docs, recipes, making a plugin, etc. check out our docs!

Check out the documentation for v4.0.0! Excuse our dust; these docs might be behind while we get everything updated. Please open an issue if something isn't working.
Using the older v3.9.1? Check out the documentation at the v3.9.1 tag!

Sample `gulpfile.js`

This file will give you a taste of what gulp does.

var gulp = require('gulp');
var less = require('gulp-less');
var babel = require('gulp-babel');
var concat = require('gulp-concat');
var uglify = require('gulp-uglify');
var rename = require('gulp-rename');
var cleanCSS = require('gulp-clean-css');
var del = require('del');
 
var paths = {
  styles: {
    src: 'src/styles/**/*.less',
    dest: 'assets/styles/'
  },
  scripts: {
    src: 'src/scripts/**/*.js',
    dest: 'assets/scripts/'
  }
};
 
/* Not all tasks need to use streams, a gulpfile is just another node program
 * and you can use all packages available on npm, but it must return either a
 * Promise, a Stream or take a callback and call it
 */
function clean() {
  // You can use multiple globbing patterns as you would with `gulp.src`,
  // for example if you are using del 2.0 or above, return its promise
  return del([ 'assets' ]);
}
 
/*
 * Define our tasks using plain functions
 */
function styles() {
  return gulp.src(paths.styles.src)
    .pipe(less())
    .pipe(cleanCSS())
    // pass in options to the stream
    .pipe(rename({
      basename: 'main',
      suffix: '.min'
    }))
    .pipe(gulp.dest(paths.styles.dest));
}
 
function scripts() {
  return gulp.src(paths.scripts.src, { sourcemaps: true })
    .pipe(babel())
    .pipe(uglify())
    .pipe(concat('main.min.js'))
    .pipe(gulp.dest(paths.scripts.dest));
}
 
function watch() {
  gulp.watch(paths.scripts.src, scripts);
  gulp.watch(paths.styles.src, styles);
}
 
/*
 * You can use CommonJS `exports` module notation to declare tasks
 */
exports.clean = clean;
exports.styles = styles;
exports.scripts = scripts;
exports.watch = watch;
 
/*
 * Specify if tasks run in series or parallel using `gulp.series` and `gulp.parallel`
 */
var build = gulp.series(clean, gulp.parallel(styles, scripts));
 
/*
 * You can still use `gulp.task` to expose tasks
 */
gulp.task('build', build);
 
/*
 * Define default task that can be called by just running `gulp` from cli
 */
gulp.task('default', build);

Use latest JavaScript version in your gulpfile

Node already supports a lot of ES2015, to avoid compatibility problem we suggest to install Babel and rename your gulpfile.js as gulpfile.babel.js.

npm install --save-dev babel-register babel-preset-es2015

Then create a .babelrc file with the preset configuration.

{
  "presets": [ "es2015" ]
}

And here's the same sample from above written in ES2015.

import gulp from 'gulp';
import less from 'gulp-less';
import babel from 'gulp-babel';
import concat from 'gulp-concat';
import uglify from 'gulp-uglify';
import rename from 'gulp-rename';
import cleanCSS from 'gulp-clean-css';
import del from 'del';
 
const paths = {
  styles: {
    src: 'src/styles/**/*.less',
    dest: 'assets/styles/'
  },
  scripts: {
    src: 'src/scripts/**/*.js',
    dest: 'assets/scripts/'
  }
};
 
/*
 * For small tasks you can export arrow functions
 */
export const clean = () => del([ 'assets' ]);
 
/*
 * You can also declare named functions and export them as tasks
 */
export function styles() {
  return gulp.src(paths.styles.src)
    .pipe(less())
    .pipe(cleanCSS())
    // pass in options to the stream
    .pipe(rename({
      basename: 'main',
      suffix: '.min'
    }))
    .pipe(gulp.dest(paths.styles.dest));
}
 
export function scripts() {
  return gulp.src(paths.scripts.src, { sourcemaps: true })
    .pipe(babel())
    .pipe(uglify())
    .pipe(concat('main.min.js'))
    .pipe(gulp.dest(paths.scripts.dest));
}
 
 /*
  * You could even use `export as` to rename exported tasks
  */
function watchFiles() {
  gulp.watch(paths.scripts.src, scripts);
  gulp.watch(paths.styles.src, styles);
}
export { watchFiles as watch };
 
/*
 * You can still use `gulp.task`
 * for example to set task names that would otherwise be invalid
 */
const clean = gulp.series(clean, gulp.parallel(styles, scripts));
gulp.task('clean', clean);
 
/*
 * Export a default task
 */
export default build;

Incremental Builds

You can filter out unchanged files between runs of a task using the gulp.src function's since option and gulp.lastRun:

const paths = {
  ...
  images: {
    src: 'src/images/**/*.{jpg,jpeg,png}',
    dest: 'build/img/'
  }
}
 
function images() {
  return gulp.src(paths.images.src, {since: gulp.lastRun(images)})
    .pipe(imagemin({optimizationLevel: 5}))
    .pipe(gulp.dest(paths.images.dest));
}
 
function watch() {
  gulp.watch(paths.images.src, images);
}

Task run times are saved in memory and are lost when gulp exits. It will only save time during the watch task when running the images task for a second time.

If you want to compare modification time between files instead, we recommend these plugins:

gulp-changed;
or gulp-newer - supports many:1 source:dest.

gulp-newer example:

function images() {
  var dest = 'build/img';
  return gulp.src(paths.images)
    .pipe(newer(dest))  // pass through newer images only
    .pipe(imagemin({optimizationLevel: 5}))
    .pipe(gulp.dest(dest));
}

If you can't simply filter out unchanged files, but need them in a later phase of the stream, we recommend these plugins:

gulp-cached - in-memory file cache, not for operation on sets of files
gulp-remember - pairs nicely with gulp-cached

gulp-remember example:

function scripts() {
  return gulp.src(scriptsGlob)
    .pipe(cache('scripts'))    // only pass through changed files
    .pipe(header('(function () {')) // do special things to the changed files...
    .pipe(footer('})();'))     // for example,
                               // add a simple module wrap to each file
    .pipe(remember('scripts')) // add back all files to the stream
    .pipe(concat('app.js'))    // do things that require all files
    .pipe(gulp.dest('public/'))
}