@eslint/core

What is @eslint/core?

@eslint/core is the core library for ESLint, a tool for identifying and fixing problems in JavaScript code. It provides the core functionality needed to lint JavaScript code, including parsing, rule application, and reporting.

What are @eslint/core's main functionalities?

Linting JavaScript Code

This feature allows you to lint JavaScript files using ESLint. The code sample demonstrates how to use the ESLint class to lint files in a project, returning results that include any linting errors or warnings.

const { ESLint } = require("@eslint/core");

(async function main() {
  const eslint = new ESLint();
  const results = await eslint.lintFiles(["src/**/*.js"]);
  console.log(results);
})();

Custom Rule Definition

This feature allows you to define custom linting rules. The code sample shows how to create a custom rule that reports an error when the identifier 'foo' is used, and how to apply this rule using ESLint.

const { ESLint } = require("@eslint/core");

const customRule = {
  create(context) {
    return {
      Identifier(node) {
        if (node.name === 'foo') {
          context.report({ node, message: "Avoid using 'foo' as an identifier." });
        }
      }
    };
  }
};

(async function main() {
  const eslint = new ESLint({
    overrideConfig: {
      rules: {
        'no-foo': ['error', customRule]
      }
    }
  });
  const results = await eslint.lintText("const foo = 1;");
  console.log(results);
})();

Configuring ESLint

This feature allows you to configure ESLint with specific environments, rules, and configurations. The code sample demonstrates how to set up ESLint with a custom configuration, including environment settings and specific rules.

const { ESLint } = require("@eslint/core");

(async function main() {
  const eslint = new ESLint({
    overrideConfig: {
      env: {
        browser: true,
        node: true
      },
      extends: "eslint:recommended",
      rules: {
        semi: ["error", "always"]
      }
    }
  });
  const results = await eslint.lintFiles(["src/**/*.js"]);
  console.log(results);
})();

Other packages similar to @eslint/core

jshint

JSHint is a static code analysis tool used to detect errors and potential problems in JavaScript code. It is similar to ESLint in that it provides linting capabilities, but it is generally considered less configurable and less extensible than ESLint.

tslint

TSLint is a linter for TypeScript, similar to ESLint but specifically designed for TypeScript. It has been deprecated in favor of using ESLint with TypeScript support, as ESLint provides a more flexible and extensible architecture.

stylelint

Stylelint is a linter for CSS and other style-related languages. While it serves a different purpose than ESLint, it is similar in that it provides linting capabilities for a specific type of code, focusing on style sheets rather than JavaScript.

README

ESLint Core

Overview

This package is the future home of the rewritten, runtime-agnostic ESLint core.

Right now, it exports the core types necessary to implement language plugins.

License

Apache 2.0

Sponsors

The following companies, organizations, and individuals support ESLint's ongoing maintenance and development. Become a Sponsor to get your logo on our READMEs and website.

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Technology Sponsors

Technology sponsors allow us to use their products and services for free as part of a contribution to the open source ecosystem and our work.