JavaScript

Last modified: 26 July 2021

With WebStorm, you can develop modern web, mobile, and desktop applications with JavaScript and Node.js.

WebStorm also supports React, Angular, Vue.js, and other frameworks and provides tight integration with various tools for web development.

JavaScript-aware coding assistance includes completion for keywords, labels, variables, parameters, and functions, error and syntax highlighting, formatting, numerous code inspections and quick-fixes, as well as common and JavaScript-specific refactoring. WebStorm also integrates with JavaScript linters and the Flow type checker.

With WebStorm built-in debugger, you can debug both your client-side and server-side code and even run JavaScript code snippets in the interactive debugger console. Learn more from Debug JavaScript in Chrome.

WebStorm integrates with Jest, Karma, Protractor, Cucumber, and Mocha testing frameworks. WebStorm supports running and debugging tests as well as navigation between tests and subjects or between a failed test and the fragment of code that caused the problem.

On this page you will find a short Getting Started Guide that will walk you step by step from creating a web application to debugging and testing it.

Creating a new application

Starting with an existing JavaScript application

If you are going to continue developing an existing JavaScript application, open it in WebStorm, choose the JavaScript version to use, and configure the libraries in it. Optionally download the required npm dependencies.

Open the application sources that are already on your machine

  • Click Open on the Welcome screen or select File | Open from the main menu. In the dialog that opens, select the folder where your sources are stored.

Check out the application sources from your version control

  1. Click Get from VCS on the Welcome screen or select VCS | Get from Version Control from the main menu.

  2. In the invoked dialog, select your version control system from the list and specify the repository to check out the application sources from.

Choosing the JavaScript language version

To get reliable and efficient coding assistance, you need to specify the language version that will be used in all JavaScript files of your project by default.

Using multiple JavaScript versions

If you are working on an application that uses both ECMAScript 5.1 and a newer version of ECMAScript, the easiest way is to choose the highest language version for the whole project from the list on the JavaScript page.

JSX syntax in JavaScript code

If you are using JSX syntax in your JavaScript code, enable ECMAScript 6+.

Downloading project dependencies

If your application uses some tools, libraries, or frameworks, download the required packages. To manage your project dependencies, you can use npm, Yarn 1, or Yarn 2, see npm and Yarn for details.

Install a package in an empty project

  • In the embedded Terminal (Alt+F12), type:

    npm install <package name>.

If you already have a package.json file in your project

  • Right-click the package.json file in the editor or in the Project tool window and choose Run 'npm install' from the context menu.

  • Alternatively, run npm install in the Terminal Alt+F12.

note

Before you start, make sure you have Node.js on your computer.

Configuring code completion for project dependencies

To provide code completion for project dependencies, WebStorm automatically creates a node_modules library. In WebStorm, a library is a file or a set of files whose functions and methods are added to WebStorm's internal knowledge in addition to the functions and methods that WebStorm retrieves from the project code that you edit. See Configure JavaScript libraries, Code completion, and Configuring code completion in JavaScript for details and examples.

Viewing parameter hints

Parameter hints show the names of parameters in methods and functions to make your code easier to read. By default, parameter hints are shown only for values that are literals or function expressions but not for named objects.

Parameter hints in JavaScript

Configure parameter hints

  1. Open the Settings/Preferences dialog Ctrl+Alt+S and go to Editor | Inlay Hints | JavaScript.

  2. Select Parameter hints from the list, make sure the Show parameter hints checkbox is selected, and then specify the context where you want parameter hints shown.

  3. For some methods and functions, WebStorm does not show parameter hints in any context. Click Exclude list... to view these methods and functions, possibly enable parameter hints for them, or add new items to the list.

tip

To hide parameter hints for all types of values, clear the Show parameter name hints checkbox. Learn more from Viewing method parameter information.

Auto-import in JavaScript

WebStorm can generate import statements for modules, classes, components, and any other symbols that are exported. If you are using ES6 in your project, WebStorm can add missing import statements on the fly, when you complete ES6 symbols.

https://resources.jetbrains.com/help/img/idea/2021.1/ws_es6_auto-import.png
Gif

For earlier JavaScript versions or when auto-import on completion is disabled, WebStorm marks the symbol as unresolved and shows a tooltip with the suggested quick-fix:

ws_es6_autoimport_off_tooltip.png

Alternatively, press Alt+Enter:

Autoimport with quick-fix: suggestion list

If there's more than one possible source of import, WebStorm shows a list of suggestions:

Autoimport with quick-fix: multiple choices

Learn more from Choosing the JavaScript language version.

WebStorm can also generate import statements for symbols defined in the project’s dependencies. Auto-import works for symbols from packages that contain TypeScript definition files (like in moment or redux) or sources written as ES modules.

https://resources.jetbrains.com/help/img/idea/2021.1/ws_auto_import_from_node_modules.png
Gif

Configure auto-import

  1. To automatically add ES6 import statements on code completion, open the Settings/Preferences dialog Ctrl+Alt+S, go to Editor | General | Auto Import, and select the Add ES6 imports on code completion checkbox in the TypeScript/JavaScript area.

  2. To configure the appearance of import statements, open the Settings/Preferences dialog Ctrl+Alt+S, go to Editor | Code Style | JavaScript, and use the controls in the Imports tab, see Imports tab for details.

Configuring syntax highlighting

You can configure JavaScript-aware syntax highlighting according to your preferences and habits.

Running JavaScript in browser

Debugging JavaScript

WebStorm provides a built-in debugger for your client-side JavaScript code that works with Chrome.

You can also debug your client-side JavaScript in Firefox, version 36 and later. However it is strongly recommended that you use Chrome or any other browser of the Chrome family. With WebStorm, you can debug JavaScript applications running on the built-in server, on an external server, or on a remote server. For details, see Debug JavaScript in Chrome and Debug JavaScript in Firefox.