gulp-changed

Only pass through changed files

No more wasting precious time on processing unchanged files.

By default it's only able to detect whether files in the stream changed. If you require something more advanced like knowing if imports/dependencies changed, create a custom comparator, or use another plugin.

Install

$ npm install --save-dev gulp-changed

Usage

const gulp = require('gulp');
const changed = require('gulp-changed');
const ngAnnotate = require('gulp-ng-annotate'); // just as an example

const SRC = 'src/*.js';
const DEST = 'dist';

gulp.task('default', () => {
	return gulp.src(SRC)
		.pipe(changed(DEST))
		// ngAnnotate will only get the files that
		// changed since the last time it was run
		.pipe(ngAnnotate())
		.pipe(gulp.dest(DEST));
});

API

changed(destination, options)

destination

Type: string, function

The destination directory. Same as you put into gulp.dest().

This is needed to be able to compare the current files with the destination files.

Can also be a function returning a destination directory path.

options

cwd

Type: string
Default: process.cwd()

The working directory the folder is relative to.

extension

Type: string

Extension of the destination files.

Useful if it differs from the original, like in the example below:

gulp.task('jade', () => {
	return gulp.src('src/**/*.jade')
		.pipe(changed('app', {extension: '.html'}))
		.pipe(jade())
		.pipe(gulp.dest('app'))
});

hasChanged

Type: function
Default: changed.compareLastModifiedTime

Function that determines whether the source file is different from the destination file.

Built-in comparators

• changed.compareLastModifiedTime
• changed.compareSha1Digest

Example

gulp.task('jade', () => {
	return gulp.src('src/**/*.jade')
		.pipe(changed('app', {hasChanged: changed.compareSha1Digest}))
		.pipe(jade())
		.pipe(gulp.dest('app'));
});

You can also supply a custom comparator function which will receive the following arguments:

• stream (transform object stream) - should be used to queue sourceFile if it passes some comparison
• callback (function) - should be called when done
• sourceFile (vinyl file object)
• destPath (string) - destination for sourceFile as an absolute path

In-place change monitoring

If you're looking to process source files in-place without any build output (formatting, linting, etc), have a look at gulp-changed-in-place.

License

MIT © Sindre Sorhus