JetBrains: ESLint

 

ESLint

WebStorm integrates with ESLint which brings a wide range of linting rules that can also be extended with plugins. WebStorm shows warnings and errors reported by ESLint right in the editor, as you type. With ESLint, you can also use JavaScript Standard Style.

To view the description of a problem, hover over the highlighted code.

Installing, enabling, and configuring ESLint in WebStorm

  • Open the built-in WebStorm Terminal (⌥F12) and type npm install eslint --save-dev or npm install eslint -g at the command prompt.

  • Optionally, install additional plugins, for example, eslint-plugin-react to lint React applications.

  • In the Settings > Preferences dialog (⌘,), choose JavaScript under Languages and Frameworks and then choose ESLint under Code Quality Tools. On the ESLint page page that opens, select the Enable checkbox. After that the controls on the page become available.

  • In the Node Interpreter field, specify the path to Node.js. If you followed the standard installation procedure, WebStorm detects the path and fills in the field itself.

  • In the ESLint Package field, specify the location of the eslint or standard package.

  • Choose the configuration to use.
    • With Automatic search, WebStorm looks for a .eslintrc file or tries to detect a configuration defined under eslintConfig in a package.json. WebStorm first looks for a .eslintrc or package.json in the folder with the file to be linted, then in its parent folder, and so on up to the project root.

    • Choose Configuration File to use a custom file and specify the file location in the Path field.

  • Optionally:

    • In the Extra ESLint Options field, specify additional command line options to run ESLint with, use spaces as separators.

    • In the Additional Rules Directory field, specify the location of the files with additional code verification rules. These rules will be applied after the rules from .eslintrc or the above specified custom configuration file and accordingly will override them.

Configuring highlighting for ESLint

By default, WebStorm marks the detected errors and warnings based on the severity levels from the ESLint configuration. For example, errors are highlighted with a red squiggly line, while warnings are marked with a yellow background.

To change the severity level of a rule in the ESLint configuration

In .eslintrc or under eslintConfig in package.json, locate the rule you want to edit and set its ID to 1 (warn) or to 2 (error). Learn more from the ESLint official website.

To ignore the severity levels from the configuration

  • In the Settings > Preferences dialog (⌘,), select Editor > Inspections. The Inspections page opens.

  • In the central pane, go to JavaScript > Code quality tools > ESLint.

  • In the right-hand pane, clear the Use rule severity from the configuration file checkbox and select the severity level to use instead of the default one.

Importing code style from ESLint

You can import some of the ESLint code style rules to the WebStorm JavaScript code style settings. That enables WebStorm to use more accurate code style options for your project when auto-completing, generating, or refactoring the code or adding import statements. When you use the Reformat action, WebStorm will then no longer break properly formatted code from the ESLint perspective.

WebStorm understands ESLint configurations in all official formats: .eslintrc JSON files, package.json files with the eslintConfig field, as well as JavaScript and YAML configuration files.

  • When you open your project for the first time, WebStorm imports the code style from the project ESLint configuration automatically.

  • If your ESLint configuration is updated (manually or from your version control), open it in the editor and choose Apply ESLint Code Style Rules on the context menu:

Alternatively, just answer Yes to the “Apply code style from ESLint?” question on top of the file:

The list of applied rules is shown in the Event log tool window:

Source: ESLint