gulp4-ing

The streaming build system

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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

Documentation

For a Getting started guide, API docs, recipes, making a plugin, etc. see the documentation page!

Sample gulpfile.js

This file is just a quick sample to give you a taste of what gulp does.

``js
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 last 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.

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

Then create a .babelrc file with the preset configuration.

`js
{
"presets": [ "es2015" ]
}
`

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

`js
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 use arrow functions and export
*/
const clean = () => del([ 'assets' ]);
export { clean };

/*
* You can still 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));
}

export function watch() {
gulp.watch(paths.scripts.src, scripts);
gulp.watch(paths.styles.src, styles);
}

const build = gulp.series(clean, gulp.parallel(styles, scripts));
export { build };

/*
* 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:
`js
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:
`js
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:
`js
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/'))
}
``

Want to contribute?

Anyone can help make this project better - check out our Contributing guide!

[downloads-image]: http://img.shields.io/npm/dm/gulp.svg
[npm-url]: https://npmjs.org/package/gulp
[npm-image]: http://img.shields.io/npm/v/gulp.svg

[travis-url]: https://travis-ci.org/gulpjs/gulp
[travis-image]: http://img.shields.io/travis/gulpjs/gulp.svg

[coveralls-url]: https://coveralls.io/r/gulpjs/gulp
[coveralls-image]: http://img.shields.io/coveralls/gulpjs/gulp/master.svg

[gitter-url]: https://gitter.im/gulpjs/gulp
[gitter-image]: https://badges.gitter.im/gulpjs/gulp.png

[gulp-cached]: https://github.com/wearefractal/gulp-cached
[gulp-remember]: https://github.com/ahaurw01/gulp-remember
[gulp-changed]: https://github.com/sindresorhus/gulp-changed
[gulp-newer]: https://github.com/tschaub/gulp-newer