eslint-utils

What is eslint-utils?

The eslint-utils package provides utility functions for developers working with ESLint, a static code analysis tool for identifying problematic patterns in JavaScript code. It offers a set of APIs that can be used to manipulate and query the abstract syntax tree (AST) generated by ESLint, making it easier to create custom rules and analyze code.

What are eslint-utils's main functionalities?

AST Utilities

Provides functions to interact with the AST, such as finding variables, their references, and their definitions within the code.

{"findVariable": "function (initializer) { return getVariableByName(initializer, 'myVariable'); }"}

Reference Utilities

Offers methods to determine if a variable is being used in the code, which can help in identifying unused variables and potential bugs.

{"isUsedVariable": "function (variable) { return isUsedVariable(variable); }"}

Scope Analysis

Allows for analysis of variable scope, which can be used to ensure that variables are declared and used within the correct scope.

{"getInnermostScope": "function (scope, node) { return getInnermostScope(scope, node); }"}

Other packages similar to eslint-utils

eslint

ESLint is the core package that eslint-utils is designed to complement. It provides the framework for static code analysis, including parsing code into an AST, managing rules, and reporting issues. eslint-utils offers additional utilities that can be used within the context of ESLint's ecosystem.

babel-eslint

babel-eslint is a parser that allows ESLint to run on source code that is transpiled with Babel. While it does not provide utility functions like eslint-utils, it serves a similar purpose in extending the capabilities of ESLint to work with a wider range of JavaScript syntax.

typescript-eslint

typescript-eslint is a plugin that enables ESLint to support TypeScript, a superset of JavaScript. It includes a parser and a set of rules specifically designed for TypeScript code. Like eslint-utils, it extends the functionality of ESLint but is focused on TypeScript rather than providing general utility functions.

README

eslint-utils

🏁 Goal

This package provides utility functions and classes for make ESLint custom rules.

For examples:

• getStaticValue evaluates static value on AST.
• PatternMatcher finds a regular expression pattern as handling escape sequences.
• ReferenceTracker checks the members of modules/globals as handling assignments and destructuring.

📖 Usage

See documentation.

📰 Changelog

See releases.

❤️ Contributing

Welcome contributing!

Please use GitHub's Issues/PRs.

Development Tools

• npm test runs tests and measures coverage.
• npm run clean removes the coverage result of npm test command.
• npm run coverage shows the coverage result of the last npm test command.
• npm run lint runs ESLint.
• npm run watch runs tests on each file change.