npm install gulp-pre[![NPM version][npm-image]][npm-url] [![Downloads][downloads-image]][npm-url] [![Support us][gittip-image]][gittip-url] [![Build Status][travis-image]][travis-url] [![Coveralls Status][coveralls-image]][coveralls-url] [![Gitter chat][gitter-image]][gitter-url]
For a Getting started guide, API docs, recipes, making a plugin, etc. see the documentation page!
gulpfile.jsThis file is just a quick sample to give you a taste of what gulp does.
``js
var gulp = require('gulp');
var coffee = require('gulp-coffee');
var concat = require('gulp-concat');
var uglify = require('gulp-uglify');
var imagemin = require('gulp-imagemin');
var sourcemaps = require('gulp-sourcemaps');
var del = require('del');
var paths = {
scripts: ['client/js//.coffee', '!client/external//.coffee'],
images: 'client/img/*/'
};
/ Register some tasks to expose to the cli /
gulp.task('build', gulp.series(
clean,
gulp.parallel(scripts, images)
));
gulp.task(clean);
gulp.task(watch);
// The default task (called when you run gulp from cli)
gulp.task('default', gulp.series('build'));
/ Define our tasks using plain functions /
// 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 or Stream or take a Callback and call it
function clean() {
// You can use multiple globbing patterns as you would with gulp.src
// If you are using del 2.0 or above, return its promise
return del(['build']);
}
// Copy all static images
function images() {
return gulp.src(paths.images)
// Pass in options to the task
.pipe(imagemin({optimizationLevel: 5}))
.pipe(gulp.dest('build/img'));
}
// Minify and copy all JavaScript (except vendor scripts)
// with sourcemaps all the way down
function scripts() {
return gulp.src(paths.scripts)
.pipe(sourcemaps.init())
.pipe(coffee())
.pipe(uglify())
.pipe(concat('all.min.js'))
.pipe(sourcemaps.write())
.pipe(gulp.dest('build/js'));
}
// Rerun the task when a file changes
function watch() {
gulp.watch(paths.scripts, scripts);
gulp.watch(paths.images, images);
}
`
You can filter out unchanged files between runs of a task using
the gulp.src function's since option and gulp.lastRun:`js
function images() {
return gulp.src(paths.images, {since: gulp.lastRun('images')})
.pipe(imagemin({optimizationLevel: 5}))
.pipe(gulp.dest('build/img'));
}
function watch() {
gulp.watch(paths.images, images);
}
`watch
Task run times are saved in memory and are lost when gulp exits. It will only
save time during the 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/'))
}
Anyone can help make this project better - check out the Contributing guide!

[gittip-url]: https://www.gittip.com/WeAreFractal/
[gittip-image]: http://img.shields.io/gittip/WeAreFractal.svg
[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