Concat scripts in order with Gulp

Say, for example, you are building a project on Backbone or whatever and you need to load scripts in a certain order, e.g. underscore.js needs to be loaded before backbone.js.

How do I get it to concat the scripts so that they’re in order?

// JS concat, strip debugging and minify
gulp.task('scripts', function() {
	gulp.src(['./source/js/*.js', './source/js/**/*.js'])
	.pipe(concat('script.js'))
	.pipe(stripDebug())
	.pipe(uglify())
	.pipe(gulp.dest('./build/js/'));
});

I have the right order of scripts in my source/index.html, but since files are organized by alphabetic order, gulp will concat underscore.js after backbone.js, and the order of the scripts in my source/index.html does not matter, it looks at the files in the directory.

So does anyone have an idea on this?

Best idea I have is to rename the vendor scripts with 1, 2, 3 to give them the proper order, but I am not sure if I like this.

As I learned more I found Browserify is a great solution, it can be a pain at first but it’s great.

I had a similar problem recently with Grunt when building my AngularJS app. Here's a question I posted.

What I ended up doing is to explicitly list the files in order in the grunt config. The config file will then look like this:

[  '/path/to/app.js',  '/path/to/mymodule/mymodule.js',  '/path/to/mymodule/mymodule/*.js']

Grunt is able to figure out which files are duplicates and not include them. The same technique will work with Gulp as well.

Another thing that helps if you need some files to come after a blob of files, is to exclude specific files from your glob, like so:

[
  '/src/**/!(foobar)*.js', // all files that end in .js EXCEPT foobar*.js
  '/src/js/foobar.js',
]

You can combine this with specifying files that need to come first as explained in Chad Johnson's answer.

I have used the gulp-order plugin but it is not always successful as you can see by my stack overflow post https://stackoverflow.com/questions/23501495/gulp-order-node-module-with-merged-streams. When browsing through the Gulp docs I came across the streamque module which has worked quite well for specifying order of in my case concatenation. https://github.com/gulpjs/gulp/blob/master/docs/recipes/using-multiple-sources-in-one-task.md

Example of how I used it is below

var gulp         = require('gulp');
var concat       = require('gulp-concat');
var handleErrors = require('../util/handleErrors');
var streamqueue  = require('streamqueue');

gulp.task('scripts', function() {
    return streamqueue({ objectMode: true },
        gulp.src('./public/angular/config/*.js'),
        gulp.src('./public/angular/services/**/*.js'),
        gulp.src('./public/angular/modules/**/*.js'),
        gulp.src('./public/angular/primitives/**/*.js'),
        gulp.src('./public/js/**/*.js')
    )
        .pipe(concat('app.js'))
        .pipe(gulp.dest('./public/build/js'))
        .on('error', handleErrors);
});

With gulp-useref you can concatenate every script declared in your index file, in the order in which you declare it.

https://www.npmjs.com/package/gulp-useref

var $ = require('gulp-load-plugins')();
gulp.task('jsbuild', function () {
  var assets = $.useref.assets({searchPath: '{.tmp,app}'});
  return gulp.src('app/**/*.html')
    .pipe(assets)
    .pipe($.if('*.js', $.uglify({preserveComments: 'some'})))
    .pipe(gulp.dest('dist'))
    .pipe($.size({title: 'html'}));
});

And in the HTML you have to declare the name of the build file you want to generate, like this:

<!-- build:js js/main.min.js -->
    <script src="js/vendor/vendor.js"></script>
    <script src="js/modules/test.js"></script>
    <script src="js/main.js"></script>

In your build directory you will have the reference to main.min.js which will contain vendor.js, test.js, and main.js

The sort-stream may also be used to ensure specific order of files with gulp.src. Sample code that puts the backbone.js always as the last file to process:

var gulp = require('gulp');
var sort = require('sort-stream');
gulp.task('scripts', function() {
gulp.src(['./source/js/*.js', './source/js/**/*.js'])
  .pipe(sort(function(a, b){
    aScore = a.path.match(/backbone.js$/) ? 1 : 0;
    bScore = b.path.match(/backbone.js$/) ? 1 : 0;
    return aScore - bScore;
  }))
  .pipe(concat('script.js'))
  .pipe(stripDebug())
  .pipe(uglify())
  .pipe(gulp.dest('./build/js/'));
});

I just add numbers to the beginning of file name:

0_normalize.scss
1_tikitaka.scss
main.scss

It works in gulp without any problems.

I have my scripts organized in different folders for each package I pull in from bower, plus my own script for my app. Since you are going to list the order of these scripts somewhere, why not just list them in your gulp file? For new developers on your project, it's nice that all your script end-points are listed here. You can do this with gulp-add-src:

gulpfile.js

var gulp = require('gulp'),
    less = require('gulp-less'),
    minifyCSS = require('gulp-minify-css'),
    uglify = require('gulp-uglify'),
    concat = require('gulp-concat'),
    addsrc = require('gulp-add-src'),
    sourcemaps = require('gulp-sourcemaps');

// CSS & Less
gulp.task('css', function(){
    gulp.src('less/all.less')
        .pipe(sourcemaps.init())
        .pipe(less())
        .pipe(minifyCSS())
        .pipe(sourcemaps.write('source-maps'))
        .pipe(gulp.dest('public/css'));
});

// JS
gulp.task('js', function() {
    gulp.src('resources/assets/bower/jquery/dist/jquery.js')
    .pipe(addsrc.append('resources/assets/bower/bootstrap/dist/js/bootstrap.js'))
    .pipe(addsrc.append('resources/assets/bower/blahblah/dist/js/blah.js'))
    .pipe(addsrc.append('resources/assets/js/my-script.js'))
    .pipe(sourcemaps.init())
    .pipe(concat('all.js'))
    .pipe(uglify())
    .pipe(sourcemaps.write('source-maps'))
    .pipe(gulp.dest('public/js'));
});

gulp.task('default',['css','js']);

Note: jQuery and Bootstrap added for demonstration purposes of order. Probably better to use CDNs for those since they are so widely used and browsers could have them cached from other sites already.

Try stream-series. It works like merge-stream/event-stream.merge() except that instead of interleaving, it appends to the end. It doesn't require you to specify the object mode like streamqueue, so your code comes out cleaner.

var series = require('stream-series');

gulp.task('minifyInOrder', function() {
    return series(gulp.src('vendor/*'),gulp.src('extra'),gulp.src('house/*'))
        .pipe(concat('a.js'))
        .pipe(uglify())
        .pipe(gulp.dest('dest'))
});

merge2 looks like the only working and maintained ordered stream merging tool at the moment.

Update 2020

The APIs are always changing, some libraries become unusable or contain vulnerabilities, or their dependencies contain vulnerabilities, that are not fixed for years. For text files manipulations you'd better use custom NodeJS scripts and popular libraries like globby and fs-extra along with other libraries without Gulp, Grunt, etc wrappers.

import globby from 'globby';
import fs from 'fs-extra';

async function bundleScripts() {
    const rootPaths = await globby('./source/js/*.js');
    const otherPaths = (await globby('./source/**/*.js'))
        .filter(f => !rootFiles.includes(f));
    const paths = rootPaths.concat(otherPaths);

    const files = Promise.all(
        paths.map(
            // Returns a Promise
            path => fs.readFile(path, {encoding: 'utf8'})
        )
    );

    let bundle = files.join('\n');
    bundle = uglify(bundle);
    bundle = whatever(bundle);
    bundle = bundle.replace(/\/\*.*?\*\//g, '');

    await fs.outputFile('./build/js/script.js', bundle, {encoding: 'utf8'});
}

bundleScripts.then(() => console.log('done');

An alternative method is to use a Gulp plugin created specifically for this problem. https://www.npmjs.com/package/gulp-ng-module-sort

It allows you to sort your scripts by adding in a .pipe(ngModuleSort()) as such:

var ngModuleSort = require('gulp-ng-module-sort');
var concat = require('gulp-concat');

gulp.task('angular-scripts', function() {
	return gulp.src('./src/app/**/*.js')
		.pipe(ngModuleSort())
		.pipe(concat('angularAppScripts.js))
		.pipe(gulp.dest('./dist/));
});

Assuming a directory convention of:

|——— src/
|   |——— app/
|       |——— module1/
|           |——— sub-module1/
|               |——— sub-module1.js
|           |——— module1.js
|       |——— module2/
|           |——— sub-module2/
|               |——— sub-module2.js
|           |——— sub-module3/
|               |——— sub-module3.js
|           |——— module2.js
|   |——— app.js

Hope this helps!

For me I had natualSort() and angularFileSort() in pipe which was reordering the files. I removed it and now it works fine for me

$.inject( // app/**/*.js files
    gulp.src(paths.jsFiles)
      .pipe($.plumber()), // use plumber so watch can start despite js errors
      //.pipe($.naturalSort())
      //.pipe($.angularFilesort()),
    {relative: true}))

I just use gulp-angular-filesort

function concatOrder() {

    return gulp.src('./build/src/app/**/*.js')
        .pipe(sort())
        .pipe(plug.concat('concat.js'))
        .pipe(gulp.dest('./output/'));
}

I'm in a module environnement where all are core-dependents using gulp. So, the core module needs to be appended before the others.

What I did:

1. Move all the scripts to an src folder

2. Just gulp-rename your core directory to _core

3. gulp is keeping the order of your gulp.src, my concat src looks like this:

    concat: ['./client/src/js/*.js', './client/src/js/**/*.js', './client/src/js/**/**/*.js']
   

It'll obviously take the _ as the first directory from the list (natural sort?).

Note (angularjs): I then use gulp-angular-extender to dynamically add the modules to the core module. Compiled it looks like this:

angular.module('Core', ["ui.router","mm.foundation",(...),"Admin","Products"])

Where Admin and Products are two modules.

if you would like to order third party libraries dependencies, try wiredep. This package basically checks each package dependency in bower.json then wire them up for you.

I tried several solutions from this page, but none worked. I had a series of numbered files which I simply wanted be ordered by alphabetical foldername so when piped to concat() they'd be in the same order. That is, preserve the order of the globbing input. Easy, right?

Here's my specific proof-of-concept code (print is just to see the order printed to the cli):

var order = require('gulp-order');
var gulp = require('gulp');
var print = require('gulp-print').default;

var options = {};

options.rootPath = {
  inputDir: process.env.INIT_CWD + '/Draft',
  inputGlob: '/**/*.md',
};

gulp.task('default', function(){
  gulp.src(options.rootPath.inputDir + options.rootPath.inputGlob, {base: '.'})
    .pipe(order([options.rootPath.inputDir + options.rootPath.inputGlob]))
    .pipe(print());
});

The reason for the madness of gulp.src? I determined that gulp.src was running async when I was able to use a sleep() function (using a .map with sleeptime incremented by index) to order the stream output properly.

The upshot of the async of src mean dirs with more files in it came after dirs with fewer files, because they took longer to process.

In my gulp setup, I'm specifying the vendor files first and then specifying the (more general) everything, second. And it successfully puts the vendor js before the other custom stuff.

gulp.src([
  // vendor folder first
  path.join(folder, '/vendor/**/*.js'),
  // custom js after vendor
  path.join(folder, '/**/*.js')
])    

Apparently you can pass in the "nosort" option to gulp.src gulp.src.