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Linting TypeScript

Last modified: 11 February 2024

Required plugin:

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

The recommended linter for TypeScript code is ESLint which brings a wide range of linting rules that can also be extended with plugins. RubyMine shows warnings and errors reported by ESLint right in the editor, as you type. Learn more from ESLint.

note

You can also use TSLint as described below. Note that TSLint has been deprecated as of 2019. For more information, refer to the TSLint official website.

RubyMine highlights errors reported by ESLint in .ts and .tsx files when @typescript-eslint/parser is set as a parser in your project ESLint configuration. Learn more from the readme file in the typescript-eslint repo.

Install and configure ESLint

  1. In the embedded Terminal (AltF12) , type one of the following commands:

    • npm install --g eslint for global installation.

    • npm install --save-dev eslint to install ESLint as a development dependency.

  2. By default, ESLint is disabled. Enable it on the Settings | Languages and Frameworks | JavaScript | Code Quality Tools | ESLint as described in Activate and configure ESLint in RubyMine".

Use ESLint for TypeScript in a new project

  1. In the embedded Terminal (AltF12) , type:

    npm install @typescript-eslint/parser @typescript-eslint/eslint-plugin --save-dev

    note

    If you installed ESLint globally, install @typescript-eslint/eslint-plugin globally as well. Learn more about installation and versions compatibility from the @typescript-eslint/eslint-plugin official documentation.

  2. In the .eslintrc configuration file or under eslintConfig in package.json, add:

    {
    "parser": "@typescript-eslint/parser",
    "plugins": [
        "@typescript-eslint"
    ],
    "extends": [
        "plugin:@typescript-eslint/recommended"
    ]
}

Suppress linting TypeScript code with ESLint

  • If you are already using @typescript-eslint/parser but you do not want to check TypeScript code with ESLint, add .ts or .tsx to the .eslintignore file.

ESLint 4.0

If you are using previous versions of ESLint, you have to install babel-eslint, typescript-eslint-parser, or eslint-plugin-typescript because ESLint 4.0 and earlier do not support scoped packages.

Use babel-eslint

  1. In the embedded Terminal (AltF12) , type:

    npm install eslint babel-eslint --save-dev

    Learn more about installation and versions compatibility from the babel-eslint official documentation.

  2. In the .eslintrc configuration file or under eslintConfig in package.json, add:

    {
    "parser": "babel-eslint"
}

Use typescript-eslint-parser

  1. In the embedded Terminal (AltF12) , type:

    npm install typescript-eslint-parser --save-dev

    Learn more from the typescript-eslint-parser official documentation.

  2. In the .eslintrc configuration file or under eslintConfig in package.json, add:

    {
    "parser": "typescript-eslint-parser"
}

Use eslint-plugin-typescript

  1. In the embedded Terminal (AltF12) , type:

    npm install typescript-eslint-parser eslint-plugin-typescript --save-dev

    note

    If you installed ESLint globally, install eslint-plugin-typescript globally as well. Learn more from the eslint-plugin-typescript official documentation.

  2. In the .eslintrc configuration file or under eslintConfig in package.json, add:

    {
    "parser": "typescript-eslint-parser",
    "plugins": [
        "eslint-plugin-typescript"
    ]
}

TSLint

You can also use the TSLint code verification tool from inside RubyMine and check your TypeScript code for the most common mistakes without running the application. When the tool is activated, it lints all the opened TypeScript files and marks the detected problems.

warning

TSLint has been deprecated as of 2019. For more information, refer to the TSLint official website.

It is recommended that you check your TypeScript code using ESLint as described above.

To view the description of a problem, hover over the highlighted code. By default, RubyMine marks detected problems based on the severity levels from the TSLint configuration file. See Configuring TSLint highlighting to learn how to override these settings.

TSLint: errors and warnings are highlighted, the description of a problem is shown in a tooltip.

Before you start

  1. Download and install Node.js.

  2. Make sure a local Node.js interpreter is configured in your project: open the Settings dialog (CtrlAlt0S) and go to Languages & Frameworks | Node.js. The Node interpreter field shows the default project Node.js interpreter.

    Learn more from Configuring a local Node.js interpreter.

  3. Make sure the JavaScript and TypeScript and TSLint required plugins are enabled on the Settings | Plugins page, tab Installed. For more information, refer to Managing plugins.

Installing TSLint

  • In the embedded Terminal (AltF12) , type:

    npm install tslint typescript --save-dev

    Learn more from the TSLint official website.

Activating and configuring TSLint in RubyMine

By default, RubyMine uses the TSLint package from the project node_modules folder and the tslint.json configuration file from the folder where the current file is stored. If no tslint.json is found in the current file folder, RubyMine will look for one in its parent folders up to the project root.

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

This behavior is default in all new RubyMine projects. To enable it in a previously created project, go to Languages & Frameworks | TypeScript | TSLint in the Settings dialog (CtrlAlt0S) and select the Automatic TSLint configuration option.

You can also configure TSLint manually to use a custom TSLint package and tslint.json and specify some additional rules.

  1. In the Settings dialog (CtrlAlt0S) , go to Languages & Frameworks | TypeScript | TSLint.

  2. Select the Manual Configuration option.

  3. Specify the path to the TSLint package.

  4. In the Configuration File area, appoint the configuration to use.

    By default, RubyMine first looks for a tslint.json, tslint.yaml, or tslint.yml configuration file. RubyMine starts the search from the folder where the file to be checked is stored, then searches in the parent folder, and so on until reaches the project root. If no tslint.json, tslint.yaml, or tslint.yml configuration file is found, TSLint uses its default embedded configuration file. Accordingly, you have to define the configuration to apply either in a tslint.json, tslint.yaml, or tslint.yml configuration file, or in a custom configuration file, or rely on the default embedded configuration.

    • To have RubyMine look for a tslint.json, tslint.yaml, or tslint.yml file, choose the Automatic search option.

    • To use a custom file, choose the Configuration File option and specify the location of the file in the Path field. Choose the path from the list, or type it manually, or click the Browse button and select the relevant file from the dialog that opens.

    Learn more about configuring TSLint from the TSLint official website.

  5. If necessary, 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 tslint.json, tslint.yaml, tslint.yml, or from the above specified custom configuration file and accordingly will override them.

Configuring highlighting for TSLint

By default, RubyMine marks the detected errors and warnings based on the severity levels from the TSLint configuration file. For example, errors are highlighted with a red squiggly line, while warnings are marked with a yellow background. For more information, refer to Code inspections and Change inspection severity.

Change the severity level of a rule in the TSLint configuration

  • In TSLint configuration file, locate the rule you want to edit and set its ID to warning or to error. Learn more from the TSLint official website.

You can override the severities from the TSLint configuration file so that RubyMine 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) , go to Editor | Inspections. The Inspections page opens.

  2. In the central pane, go to TypeScript | TSLint.

  3. In the right 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 TSLint

Importing code style from a TSLint configuration file

RubyMine understands some TSLint rules that are described in tslint.json, tslint .yaml, or tslint.yml configuration files and lets you apply them to the TypeScript code style configuration in your project.

  • When you open your project for the first time, RubyMine imports the code style from the project tslint.json, tslint.yaml, or tslint.yml automatically.

  • If tslint.json, tslint.yaml, or tslint.yml is updated (manually or from your version control), open it in the editor and choose Apply TSLint Code Style Rules from the context menu.

    Import TSLint code style rules from the editor: context menu

    Alternatively, just answer Yes to the "Apply code style from TSLint?" question on top of the file.

    RubyMine suggests importing the code style from tslint.json

TSLint quick-fixes

RubyMine lets you automatically fix some of the issues that TSLint reports.

You can suppress TSLint rules for the current file and even for the current line. RubyMine automatically generates disable comments in the format /* tslint:disable:<rule name> or // tslint:disable-next-line:<rule name> and places them on top of the file or above the current line respectively.

Suppress a TSLint rule on the fly

  1. Place the caret at an error or a warning reported by TSLint and press AltEnter.

  2. Select the quick-fix for the rule that you want to disable and press 0→.

  3. From the list, select Suppress <rule name> for current file or Suppress <rule name> for current line.

    Disabling TSLint rules on the fly by adding disable comments

See also

Procedures

External Links