eslint-plugin-radar

Radar rules for ESLint to detect bugs and suspicious patterns in your code.

This is a currently maintained fork of SonarJS.

Rules

Bug Detection :bug:

Rules in this category aim to find places in code which have a high chance of being bugs, i.e. don't work as intended.

• All branches in a conditional structure should not have exactly the same implementation (no-all-duplicated-branches)
• Collection elements should not be replaced unconditionally (no-element-overwrite)
• Function calls should not pass extra arguments (no-extra-arguments)
• Related "if/else if" statements should not have the same condition (no-identical-conditions)
• Identical expressions should not be used on both sides of a binary operator (no-identical-expressions)
• Loops with at most one iteration should be refactored (no-one-iteration-loop)
• The output of functions that don't return anything should not be used (no-use-of-empty-return-value)

Code Smell Detection :pig:

Code Smells, or maintainability issues, are raised for places of code which might be costly to change in the future. These rules also help to keep the high code quality and readability. And finally some rules report issues on different suspicious code patters.

• Cognitive Complexity of functions should not be too high (cognitive-complexity)
• "switch" statements should not have too many "case" clauses (max-switch-cases)
• Collapsible "if" statements should be merged (no-collapsible-if)
• Collection sizes and array length comparisons should make sense (no-collection-size-mischeck)
• String literals should not be duplicated (no-duplicate-string)
• Two branches in a conditional structure should not have exactly the same implementation (no-duplicated-branches)
• Functions should not have identical implementations (no-identical-functions)
• Boolean checks should not be inverted (no-inverted-boolean-check) (:wrench: fixable)
• Boolean literals should not be redundant (no-redundant-boolean)
• Jump statements should not be redundant (no-redundant-jump)
• Conditionals should start on new lines (no-same-line-conditional)
• "switch" statements should have at least 3 "case" clauses (no-small-switch)
• Collection and array contents should be used (no-unused-collection)
• "catch" clauses should do more than rethrow (no-useless-catch)
• Local variables should not be declared and then immediately returned or thrown (prefer-immediate-return) (:wrench: fixable)
• Object literal syntax should be used (prefer-object-literal)
• Return of boolean expressions should not be wrapped into an "if-then-else" statement (prefer-single-boolean-return)
• A "while" loop should be used instead of a "for" loop (prefer-while) (:wrench: fixable)

Prerequisites

Node.js (>=6.x).

Usage

• If you don't have ESLint yet configured for your project, follow these instructions.
• Install eslint-plugin-radar using npm (or yarn) for you project or globally:

npm install eslint-plugin-radar --save-dev # install for your project
npm install eslint-plugin-radar -g         # or install globally

• Add eslint-plugin-radar to the plugins option of your .eslintrc:

{
  "plugins": ["radar"]
}

• Add plugin:radar/recommended to the extends option to enable all recommended rules:

{
  "extends": ["plugin:radar/recommended"]
}

• or enable only some rules manually:

{
  "rules": {
    "radar/cognitive-complexity": "error",
    "radar/no-identical-expressions": "error"
    // etc.
  }
}

Contributing

You want to participate in the development of the project? Have a look at our contributing guide!

CHANGES for eslint-plugin-radar

0.2.1

• License: Update license file name to reflect license type is specifically LGPL-3.0-only
• npm: Change license to non-deprecated SPDX identifier, LGPL-3.0-only as per: https://github.com/SonarSource/eslint-plugin-sonarjs/issues/190)

Dev-focused:

• Linting: Apply prettier to MD files and reapply latest to whole project
• npm: Revert back to using fixed rather than self-referential version of eslint-plugin-radar for self-linting (was adding to file space)

0.2.0

• Enhancement: add meta.docs (@Loxos)
• License: Rename file name to reflect license type (LGPL-3) and add extension
• Docs: Add CHANGES.md

Dev-focused:

• Travis: Check Node 15

0.1.0

• Forked from https://github.com/SonarSource/eslint-plugin-sonarjs
• License: Add headers to hidden files
• npm: Add ESLint 7 to peerDeps.
• npm: Bump engines to avoid EOL versions (Node >=10)
• npm: Use repository URL (accepted in npm, package.json linter doesn't complain, and allows IDEs to auto-open in browser (e.g., on cmd-O)
• npm: Add recommended/optional fields, author, contributors to satisfy linter

Dev-focused:

• Optimization: Add "use strict" for CJS eslint files
• Linting: Apply latest prettier (adding .prettierignore to avoid applying to test sources); apply latest eslint-plugin-import
• Linting: Check hidden files
• Linting: Check all files by default, ignoring test sources and lib
• Linting: Create separate ignore file for ruling (which lints nested node_modules)
• Testing: Ensure test-ci script runs (now that Node 8 is removed)
• Travis: Bump Node versions to 12 and 14
• Travis: Avoid comment about "nodejs 6" being cause of failure; the need for jest-sonar-reporter is due to it not being in devDeps.
• Properties: Point to non-deprecated travis-ci.com
• npm: Reorder scripts so main scripts at bottom; switch test to check coverage and add jest script for non-coverage testing
• npm: Add .ncurc.js file to prevent npm-check-updates auto-updating peerDeps.
• npm: Self-reference current version of sonarjs, so can apply latest linting to own repository
• npm: Update lint-staged, removing git add
• npm: Update devDeps.
• yarn: Upgrade