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  1. Language and framework-specific guidelines
  2. JavaScript
  3. JavaScript linters
  4. ESLint

ESLint

Last modified: 11 October 2023

Required plugin:

Javascript and TypeScript -  The plugin is bundled with CLion and enabled by default.

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

Besides JavaScript and TypeScript, ESLint can be applied to files of other types in the entire project or in its specific parts, refer to Configure linting scope.

Before you start

Install ESLint

Activate and configure ESLint in CLion

By default, ESLint is disabled. You can choose to configure it automatically or specify all the configuration settings manually.

Configure ESLint automatically

With automatic configuration, CLion uses the ESLint package from the project node_modules folder and the .eslintrc.* configuration file from the folder where the current file is stored. If no .eslintrc.* is found in the current file folder, CLion will look for one in its parent folders up to the project root.

If you have several package.json files with ESLint listed as a dependency, CLion starts a separate process for each package.json and processes everything below it. This lets you apply a specific ESLint version or a specific set of plugins to each path in a monorepo or a project with multiple ESLint configurations.

Configure ESLint manually

With manual configuration, you can use a custom ESLint package, configuration file, and working directories, as well as apply various additional rules and options.

Configure linting scope

Fix problems automatically on save

ESLint can fix the detected problems every time your changes are saved either manually, with Ctrl0S, or automatically, when you launch a run/debug configuration, or close CLion, or perform version control actions For more information, refer to Autosave.

tip

Enabling this option also enables Run eslint --fix in Settings | Tools | Actions on Save.

Lint your code

When installed and enabled, ESLint activates automatically every time you open a JavaScript file.

By default, CLion marks detected problems based on the severity levels from the ESLint configuration. See Configuring ESLint highlighting to learn how to override these settings.

Descriptions of the errors detected in the current file and quick-fixes for them are available from the editor and from the File tab of the Problems tool window.

Errors in all previously opened files and quick-fixes for them are shown in the Project Errors tab of the Problems tool window. To open the tool window, click the Inspection widget in the upper-right corner of the editor:

Inspection widget

For more information, refer to View problems and apply quick-fixes in the editor and Problems tool window.

View problems and apply quick-fixes in the editor

Lint your code in the Problems tool window

To open the Problems tool window, click the Inspections widget in the upper-right corner of the editor.

Inspection widget

Alternatively select View | Tool windows | Problems from the main menu or press Alt06.

The Project Errors tab shows the errors in all files that were opened during the current session, with error messages grouped by files in which they were detected.

Problems tool window, ESLint. Project Errors tab shows syntax errors in previously opened files across the project

Here you can view problem descriptions, apply quick-fixes, navigate to the fragments in the source code where errors occurred, as well as fix them in the Editor Preview pane without leaving the tool window. Learn more from Problems tool window.

Configure highlighting for ESLint

By default, CLion 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. For more information, refer to Static code analysis and Inspection severities.

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.

You can override the severities from the ESLint configuration so that CLion ignores them and shows everything reported by the linter as errors, warnings, or in a custom color.

Ignore the severity levels from the configuration

  1. In the Settings dialog (CtrlAlt0S), select Editor | Inspections. The Inspections page opens.

  2. In the central pane, go to JavaScript | Code quality tools | ESLint.

  3. 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.

    Specifying a custom severity level for ESLint

Import code style from ESLint

You can import some of the ESLint code style rules to the CLion JavaScript code style settings. That enables CLion 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, CLion will then no longer break properly formatted code from the ESLint perspective.

CLion 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.

Use JavaScript Standard Style

You can set JavaScript Standard Style as default JavaScript code style for your application so its main rules are applied when you type the code or reformat it. Since Standard is based on ESLint, you can also use Standard via the CLion ESLint integration.

Install JavaScript Standard

Enable linting with Standard via ESLint

If you open a project where standard is listed in the project's package.json file, CLion enables linting with Standard automatically.

  1. In the Settings dialog (CtrlAlt0S), go to Languages & Frameworks | JavaScript | Code Quality Tools | ESLint.

  2. On the ESLint page that opens, select Manual ESLint configuration and specify the location of the standard package in the ESLint Package field.

Set the JavaScript Standard Style as default

  1. In the Settings dialog (CtrlAlt0S), go to Editor | Code Style | JavaScript.

  2. On the JavaScript page, click Set from, and then select JavaScript Standard Style. The style will replace your current scheme.

ESLint with Docker

With CLion, you can run ESLint against your code inside a Docker container just in the same way as you do it locally.

Learn more from Node.js with Docker.