gulp-inject

A javascript, stylesheet and webcomponent injection plugin for Gulp, i.e. inject file references into your index.html

gulp-inject

A stylesheet, javascript and webcomponent reference injection plugin for gulp. No more manual editing of your index.html!

gulp-inject takes a stream of source files, transforms each file to a string and injects each transformed string into placeholders in the target stream files. See Basic usage and More examples below.

Default transforms and placeholders exists for injecting files into html, jade, pug, jsx , less, slm, haml and sass / scss files.

Installation

Install gulp-inject as a development dependency:

npm install --save-dev gulp-inject

Basic usage

The target file src/index.html:

Each pair of comments are the injection placeholders (aka. tags, see options.starttag and options.endtag).

<!DOCTYPE html>
<html>
<head>
  <title>My index</title>
  <!-- inject:css -->
  <!-- endinject -->
</head>
<body>
 
  <!-- inject:js -->
  <!-- endinject -->
</body>
</html>

The gulpfile.js:

var gulp = require('gulp');
var inject = require('gulp-inject');
 
gulp.task('index', function () {
  var target = gulp.src('./src/index.html');
  // It's not necessary to read the files (will speed up things), we're only after their paths: 
  var sources = gulp.src(['./src/**/*.js', './src/**/*.css'], {read: false});
 
  return target.pipe(inject(sources))
    .pipe(gulp.dest('./src'));
});

src/index.html after running gulp index:

<!DOCTYPE html>
<html>
<head>
  <title>My index</title>
  <!-- inject:css -->
  <link rel="stylesheet" href="/src/style1.css">
  <link rel="stylesheet" href="/src/style2.css">
  <!-- endinject -->
</head>
<body>
 
  <!-- inject:js -->
  <script src="/src/lib1.js"></script> 
  <script src="/src/lib2.js"></script> 
  <!-- endinject -->
</body>
</html>

More examples

Injecting files relative to target files

By default the injected file paths are relative to each source file's cwd (see options.ignorePath). If options.relative is set to true each injected path will be relative to each target file's directory instead.

Project structure:

└── src
    ├── module
    │   ├── module.js
    │   └── module.html
    └── app
        ├── main.js
        └── index.html

src/app/index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My Index</title>
</head>
<body>
  <h1>Home</h1>
  <!-- inject:js -->
  <!-- endinject -->
</body>
</html>

src/module/module.html:

<!DOCTYPE html>
<html>
<head>
  <title>Module</title>
</head>
<body>
  <h1>Module</h1>
  <!-- inject:js -->
  <!-- endinject -->
</body>
</html>

gulpfile.js:

var inject = require('gulp-inject');
 
gulp.src('./src/**/*.html')
  .pipe(inject(gulp.src('./src/**/*.js', {read: false}), {relative: true}))
  .pipe(gulp.dest('./src'));

Resulting src/app/index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My Index</title>
</head>
<body>
  <h1>Home</h1>
  <!-- inject:js -->
  <script src="main.js"></script> 
  <script src="../module/module.js"></script> 
  <!-- endinject -->
</body>
</html>

Resulting src/module/module.html:

<!DOCTYPE html>
<html>
<head>
  <title>Module</title>
</head>
<body>
  <h1>Home</h1>
  <!-- inject:js -->
  <script src="../app/main.js"></script> 
  <script src="module.js"></script> 
  <!-- endinject -->
</body>
</html>

Injecting files from multiple source streams

This example demonstrates how to inject files from multiple different streams into the same injection placeholder.

Install event-stream with: npm install --save-dev event-stream and use its merge function.

Code:

var es = require('event-stream'),
    inject = require('gulp-inject');
 
// Concatenate vendor scripts 
var vendorStream = gulp.src(['./src/vendors/*.js'])
  .pipe(concat('vendors.js'))
  .pipe(gulp.dest('./dist'));
 
// Concatenate AND minify app sources 
var appStream = gulp.src(['./src/app/*.js'])
  .pipe(concat('app.js'))
  .pipe(uglify())
  .pipe(gulp.dest('./dist'));
 
gulp.src('./src/index.html')
  .pipe(inject(es.merge(vendorStream, appStream)))
  .pipe(gulp.dest('./dist'));

Multiple sources when order is important

Use stream-series.

Code:

var series = require('stream-series'),
    inject = require('gulp-inject');
 
var vendorStream = gulp.src(['./src/vendors/*.js'], {read: false});
 
var appStream = gulp.src(['./src/app/*.js'], {read: false});
 
gulp.src('./src/index.html')
  .pipe(inject(series(vendorStream, appStream))) // This will always inject vendor files before app files 
  .pipe(gulp.dest('./dist'));

Injecting some files into `<head>` and some into `<body>`

Method 1: Use `gulp-inject`'s `starttag` option.

gulpfile.js:

var inject = require('gulp-inject');
 
gulp.src('./src/index.html')
  .pipe(inject(gulp.src('./src/importantFile.js', {read: false}), {starttag: '<!-- inject:head:{{ext}} -->'}))
  .pipe(inject(gulp.src(['./src/*.js', '!./src/importantFile.js'], {read: false})))
  .pipe(gulp.dest('./dist'));

And in your ./src/index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My index</title>
  <!-- inject:head:js -->
  <!-- only importantFile.js will be injected here -->
  <!-- endinject -->
</head>
<body>
 
  <!-- inject:js -->
  <!-- the rest of the *.js files will be injected here -->
  <!-- endinject -->
</body>
</html>

Method 2: Use `gulp-inject`'s `name` option.

gulpfile.js:

var inject = require('gulp-inject');
 
gulp.src('./src/index.html')
  .pipe(inject(gulp.src('./src/importantFile.js', {read: false}), {name: 'head'}))
  .pipe(inject(gulp.src(['./src/*.js', '!./src/importantFile.js'], {read: false})))
  .pipe(gulp.dest('./dist'));

And in your ./src/index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My index</title>
  <!-- head:js -->
  <!-- only importantFile.js will be injected here -->
  <!-- endinject -->
</head>
<body>
 
  <!-- inject:js -->
  <!-- the rest of the *.js files will be injected here -->
  <!-- endinject -->
</body>
</html>

Injecting all files for development

If you use Bower for frontend dependencies I recommend using main-bower-files and injecting them as well.

gulpfile.js:

var bowerFiles = require('main-bower-files'),
    inject = require('gulp-inject'),
    stylus = require('gulp-stylus'),
    es = require('event-stream');
 
var cssFiles = gulp.src('./src/**/*.styl')
  .pipe(stylus())
  .pipe(gulp.dest('./build'));
 
gulp.src('./src/index.html')
  .pipe(inject(gulp.src(bowerFiles(), {read: false}), {name: 'bower'}))
  .pipe(inject(es.merge(
    cssFiles,
    gulp.src('./src/app/**/*.js', {read: false})
  )))
  .pipe(gulp.dest('./build'));

src/index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My index</title>
  <!-- bower:css -->
  <!-- bower installed css files will go here... -->
  <!-- endinject -->
  <!-- inject:css -->
  <!-- built css files will go here... -->
  <!-- endinject -->
</head>
<body>
 
  <!-- bower:js -->
  <!-- bower installed scripts will go here... -->
  <!-- endinject -->
  <!-- inject:js -->
  <!-- app scripts will go here... -->
  <!-- endinject -->
</body>
</html>

Note remember to mount ./bower_components, ./build and ./src/app as static resources in your server to make this work.

Injecting AngularJS scripts for development

If you're writing an AngularJS application and follow Google's Angular APP Structure Recommendations, which I think you should, it's important that the script files are injected in the correct order to avoid module instantiation problems like Uncaught Error: [$injector:modulerr].

To do this you can use gulp-angular-filesort together with gulp-inject like so:

var angularFilesort = require('gulp-angular-filesort'),
    inject = require('gulp-inject');
 
gulp.src('./src/index.html')
  .pipe(inject(
    gulp.src('./src/app/**/*.js') // gulp-angular-filesort depends on file contents, so don't use {read: false} here 
      .pipe(angularFilesort())
    ))
  .pipe(gulp.dest('./build'));

Injecting into a json-file

You can customize gulp-inject further by using the transform function option, e.g. by injecting files into a json-file.

Code:

gulp.src('./files.json')
  .pipe(inject(gulp.src(['./src/*.js', './src/*.css', './src/*.html'], {read: false}), {
    starttag: '"{{ext}}": [',
    endtag: ']',
    transform: function (filepath, file, i, length) {
      return '  "' + filepath + '"' + (i + 1 < length ? ',' : '');
    }
  }))
  .pipe(gulp.dest('./'));

Initial contents of files.json:

{
  "js": [
  ],
  "css": [
  ],
  "html": [
  ]
}

Injecting with custom `transform` function with default fallback

The default transform function is available to use e.g. as a default fallback.

Used here to inject Word documents as <a> tags below:

index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My documents</title>
</head>
<body>
  <h1>Documents</h1>
  <ul>
    <!-- inject:docx -->
    <!-- endinject -->
  </ul>
  <!-- inject:js -->
  <!-- endinject -->
</body>
</html>

gulpfile.js:

var inject = require('gulp-inject');
 
gulp.src('./index.html')
  .pipe(inject(
    gulp.src(['./*.js', './docs/*.docx'], {read: false}), {
      transform: function (filepath) {
        if (filepath.slice(-5) === '.docx') {
          return '<li><a href="' + filepath + '">' + filepath + '</a></li>';
        }
        // Use the default transform as fallback: 
        return inject.transform.apply(inject.transform, arguments);
      }
    }
  ))
  .pipe(gulp.dest('./'));

Resulting index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My documents</title>
</head>
<body>
  <h1>Documents</h1>
  <ul>
    <!-- inject:docx -->
    <li><a href="/docs/document1.docx"></a></li>
    <li><a href="/docs/document2.docx"></a></li>
    <!-- endinject -->
  </ul>
  <!-- inject:js -->
  <script src="/lib1.js"></script> 
  <script src="/lib2.js"></script> 
  <!-- endinject -->
</body>
</html>

Injecting dist files into bower.json's main section

Code:

gulp.src('./bower.json')
  .pipe(inject(gulp.src(['./dist/app.min.js', './dist/app.min.css'], {read: false}), {
    starttag: '"main": [',
    endtag: ']',
    transform: function (filepath, file, i, length) {
      return '  "' + filepath + '"' + (i + 1 < length ? ',' : '');
    }
  }))
  .pipe(gulp.dest('./'));

Injecting all javascript files into a karma config file

Code:

gulp.src('./karma.conf.js')
  .pipe(inject(gulp.src(['./src/**/*.js'], {read: false}), {
    starttag: 'files: [',
    endtag: ']',
    transform: function (filepath, file, i, length) {
      return '  "' + filepath + '"' + (i + 1 < length ? ',' : '');
    }
  }))
  .pipe(gulp.dest('./'));

Injecting files contents

In order to inject files contents you have to provide custom transform function, that will return file contents as string. You also have to omit {read: false} option of gulp.src in this case. Example below shows how to inject contents of html partials into head of index.html:

Code:

gulp.src('./src/index.html')
  .pipe(inject(gulp.src(['./src/partials/head/*.html']), {
    starttag: '<!-- inject:head:{{ext}} -->',
    transform: function (filePath, file) {
      // return file contents as string 
      return file.contents.toString('utf8')
    }
  }))
  .pipe(gulp.dest('./dest'));

And in your ./src/index.html:

<!DOCTYPE html>
<html>
<head>
  <title>My index</title>
  <!-- inject:head:html -->
  <!-- contents of html partials will be injected here -->
  <!-- endinject -->
</head>
<body>
</body>
</html>

API

inject(sources, options)

sources

Type: Stream

Provide a Vinyl File Stream as input to inject, see examples above.

N.B: The old behavior, where you specify target as a string is deprecated since v.1.0.

options.ignorePath

Type: String or Array

Default: NULL

A path or paths that should be removed from each injected file path.

This could also be solved by setting the cwd option for your gulp.src streams, each source file's cwd is automatically removed from its path before injection (if not options.relative is set to true, see below).

options.relative

Type: Boolean

Default: false

If set to true paths for the injected files will be relative to each target file, this also means that each source file's cwd is not necessary to remove from its path.

options.addPrefix

Type: String

Default: NULL

A path that should be prefixed to each injected file path.

options.addSuffix

Type: String

Default: NULL

A path that should be suffixed to each injected file path.

options.addRootSlash

Type: Boolean

Default: !options.relative

The root slash is automatically added at the beginning of the path ('/'), or removed if set to false.

options.name

Type: String

Default: "inject"

Used in the default start and end tags below.

options.removeTags

Type: Boolean

Default: false

When true the start and end tags will be removed when injecting files.

options.empty

Type: Boolean

Default: false

When true all tags without corresponding files will be emptied.

Warning this has the potential issue of emptying more than expected.

options.starttag

Type: String|Function(targetExt, sourceExt)

Params (if function):

targetExt - The file extension of the target file
sourceExt - The file extension of source file

Purpose:

Used to dynamically set starting placeholder tag depending on file extensions. In the provided string, or the string returned from the given function, the string {{ext}} is replaced with the source file extension name, e.g. "css", "js" or "html". {{name}} will be replaced by options.name.

Default:

A function dependent on target file type and source file type that returns:

html as target: 
haml as target: -# {{name}}:{{ext}}
jade as target: //- {{name}}:{{ext}}
pug as target: //- {{name}}:{{ext}}
jsx as target: {/* {{name}}:{{ext}} */}
slm as target: / {{name}}:{{ext}}
less as target: /* {{name}}:{{ext}} */
sass, scss as target: /* {{name}}:{{ext}} */

options.endtag

Type: String|Function(targetExt, sourceExt)

Params (if function):

targetExt - The file extension of the target file
sourceExt - The file extension of source file

Purpose:

Used to dynamically set ending placeholder tag depending on file extensions. In the provided string, or the string returned from the given function, the string {{ext}} is replaced with the source file extension name, e.g. "css", "js" or "html". {{name}} will be replaced by options.name.

Default:

A function dependent on target file type and source file type that returns:

html as target: 
haml as target: -# endinject
jade as target: //- endinject
pug as target: //- endinject
jsx as target: {/* endinject */}
slm as target: / endinject
less as target: /* endinject */
sass, scss as target: /* endinject */

options.transform

Type: Function(filepath, file, index, length, targetFile)

Params:

filepath - The "unixified" path to the file with any ignorePath's removed, addPrefix and addSuffix added
file - The File object to inject given from gulp.src
index - 0-based file index
length - Total number of files to inject for the current file extension
targetFile - The target file to inject into

Purpose:

Used to generate the content to inject for each file.

Default:

A function dependent on target file type and source file type that returns:

Injecting into html

css files: <link rel="stylesheet" href="<filename>.css">
js files: <script src="<filename>.js"></script>
coffee files: <script type="text/coffeescript" src="<filename>.coffee"></script>
html files: <link rel="import" href="<filename>.html">
png files: <img src="<filename>.png">
gif files: <img src="<filename>.gif">
jpg files: <img src="<filename>.jpg">
jpeg files: <img src="<filename>.jpeg">

If options.selfClosingTag is true the default transformer above will make the <link> and <img> tags self close, i.e: <link ... /> and <img ... /> respectively.

Injecting into jsx

The same as for injecting into html above with options.selfClosingTag set to true.

Injecting into jade

css files: link(rel="stylesheet", href="<filename>.css")
js files: script(src="<filename>.js")
coffee files: script(type="text/coffeescript", src="<filename>.coffee")
html files: link(rel="import", href="<filename>.html")
png files: img(src="<filename>.png")
gif files: img(src="<filename>.gif")
jpg files: img(src="<filename>.jpg")
jpeg files: img(src="<filename>.jpeg")

Injecting into pug

css files: link(rel="stylesheet", href="<filename>.css")
js files: script(src="<filename>.js")
coffee files: script(type="text/coffeescript", src="<filename>.coffee")
html files: link(rel="import", href="<filename>.html")
png files: img(src="<filename>.png")
gif files: img(src="<filename>.gif")
jpg files: img(src="<filename>.jpg")
jpeg files: img(src="<filename>.jpeg")

Injecting into slm

css files: link rel="stylesheet" href="<filename>.css"
js files: script src="<filename>.js"
coffee files: script type="text/coffeescript" src="<filename>.coffee"
html files: link rel="import" href="<filename>.html"
png files: img src="<filename>.png"
gif files: img src="<filename>.gif"
jpg files: img src="<filename>.jpg"
jpeg files: img src="<filename>.jpeg"

Injecting into haml

css files: %link{rel:"stylesheet", href:"<filename>.css"}
js files: %script{src:"<filename>.js"}
coffee files: %script{type:"text/coffeescript", src:"<filename>.coffee"}
html files: %link{rel:"import", href:"<filename>.html"}
png files: %img{src:"<filename>.png"}
gif files: %img{src:"<filename>.gif"}
jpg files: %img{src:"<filename>.jpg"}
jpeg files: %img{src:"<filename>.jpeg"}

Injecting into less

css files: @import "<filename>.css";
less files: @import "<filename>.less";

Injecting into scss

css files: @import "<filename>.css";
scss files: @import "<filename>.scss";
sass files: @import "<filename>.sass";

Injecting into sass

css files: @import "<filename>.css"
sass files: @import "<filename>.sass"
scss files: @import "<filename>.scss"

options.selfClosingTag

Type: Boolean

Default: false

Affects the default options.transform function, see above.

options.templateString

DEPRECATED!

Deprecated since v.1.0. Use gulp-file instead:

var gulp = require('gulp');
var file = require('gulp-file');
var inject = require('gulp-inject');
 
file('index.html', '<html><head></head></html>')
  .pipe(inject(gulp.src(['./src/app/**/*.js']), {
    starttag: '<head>',
    endtag: '</head>'
  }))
  .pipe(gulp.dest('./dest'));

options.sort

DEPRECATED!

Deprecated since v.1.0. Use sort-stream instead:

var gulp = require('gulp');
var sort = require('sort-stream');
var inject = require('gulp-inject');
 
gulp.src('index.html')
  .pipe(inject(
    gulp.src(['./src/app/**/*.js'])
      .pipe(sort(function (a, b) {
      // Sort condition here... 
      }))
  ))
  .pipe(gulp.dest('./dest'));

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