Minifying JavaScript
Available only in IntelliJ IDEA Ultimate: download to try or compare editions
Required plugins:
JavaScript and TypeScript
- The plugin is bundled with IntelliJ IDEA and enabled by default. The plugin is available only in IntelliJ IDEA Ultimate.
File Watchers
- Install the plugin on the Settings | Plugins page, tab Marketplace.
Minification or compression means removing all unnecessary characters, such as spaces, new lines, comments, without changing the functionality of the source code. During development and debugging, these characters make code easier to read. At the production stage, they only increase the size of code to be transferred.
Most often compression is done as a step in your build process, with build tools like webpack. If you're not using build tools, you can use a stand-alone tool, such as UglifyJS.
To minify your code automatically, you need to install a minification tool and configure a File Watcher which will track changes to your files and run the minification tool.
By default, minification starts as soon as a JavaScript file in the File Watcher's scope is changed and saved. You can specify other events that invoke the tool. Learn more from File Watchers.
The generated minified code is stored in a separate file with the name of the source Javascript file and the extension min.js. The location of this generated file is defined in the Output paths to refresh field of the New Watcher dialog. However, in the Project Tree, the file with the minified code is shown under the source Javascript file which is displayed as a node. To change this default presentation, configure file nesting in the Project tool window .
The example below shows how you can use UglifyJS to minify your JavaScript code right from IntelliJ IDEA.
note
The example only illustrates the workflow. You can install another minification tool and configure it following the steps from the example below.
warning
UglifyJS works only with JavaScript (ES5 and earlier). For ES6 and later versions, use build tools, for example, Babel or webpack. Learn more from the UglifyJS official website.
To compress your code automatically, you need to install UglifyJS and configure a UglifyJS File Watcher which will track changes to your files and run the tool.
By default, minification starts as soon as a JavaScript file in the File Watcher's scope is changed and saved. You can specify other events that invoke UglifyJS. Learn more from File Watchers.
The generated minified code is stored in a separate file with the name of the source JavaScript file and the extension min.js. The location of this generated file is defined in the Output paths to refresh field of the New Watcher dialog. However, in the Project Tree, the file with the minified code is shown under the source JavaScript file which is displayed as a node. To change this default presentation, configure file nesting in the Project tool window .
Make sure you have Node.js on your computer.
Make sure the JavaScript and TypeScript bundled plugin is enabled in the settings. Press to open settings and then select Plugins. Click the Installed tab. In the search field, type JavaScript and TypeScript. For more information about plugins, refer to Managing plugins.
Install and enable the File Watchers plugin on the Settings | Plugins page, tab Marketplace, as described in Installing plugins from JetBrains Marketplace.
In the embedded Terminal () , type:
npm install --g uglify-js
Learn more from the UglifyJS official website.
In the Settings dialog () , click File Watchers under Tools. The File Watchers page that opens shows the list of already configured File Watchers.
Click or press and select the UglifyJS predefined template from the list.
The New Watcher dialog opens.
In the Program field, specify the location of the UglifyJS executable file.
If you installed UglifyJS through the Node Package Manager, IntelliJ IDEA locates the package itself and fills in the field automatically with the
uglifyjs
alias. Otherwise, type the path manually or click and select the file location in the dialog that opens.By default, the Scope field shows Project Files. To avoid minification of already minified files, configure a custom scope with the
file:*js&&!file:*.min.*
pattern, as described in Define a new scope.Then select the new scope from the Scopes list.
Accept the other default File Watcher settings or reconfigure them, if necessary, as described in File Watchers, and click OK. IntelliJ IDEA brings you back to the File Watchers page where the new File Watcher is added to the list:
Make sure the Enabled checkbox is selected.
By default, the File Watcher will be available in the current project. To use it in other projects, select Global from the Level list.