> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/eslint/eslint/llms.txt
> Use this file to discover all available pages before exploring further.

# Node.js API Overview

> Overview of the ESLint programmatic API

The ESLint Node.js API allows you to programmatically lint JavaScript code and integrate ESLint into your Node.js applications.

## API Exports

ESLint exports the following modules from `eslint`:

```javascript theme={null}
const { ESLint, Linter, RuleTester, SourceCode, loadESLint } = require("eslint");
```

## Primary Classes

### ESLint

The `ESLint` class is the primary Node.js API for linting files and text. It provides methods for:

* Linting files and directories
* Linting text strings
* Loading formatters
* Calculating configurations
* Getting rules metadata

[Learn more about ESLint class →](/api/eslint)

### Linter

The `Linter` class is a low-level API for verifying code with explicit configuration. It provides:

* Direct code verification with config objects
* Autofix capabilities
* Access to source code and suppressed messages

[Learn more about Linter class →](/api/linter)

### RuleTester

The `RuleTester` class is used for testing ESLint rules. It provides:

* Test framework integration (Mocha, Jest)
* Valid and invalid test cases
* Automatic assertion of rule behavior

[Learn more about RuleTester →](/api/rule-tester)

### SourceCode

The `SourceCode` class represents parsed source code. It provides:

* Access to AST, tokens, and comments
* Scope analysis information
* Methods for querying code structure

[Learn more about SourceCode →](/api/source-code)

### loadESLint

The `loadESLint` function is an async function that returns the ESLint constructor. It's primarily useful for dynamic imports and compatibility scenarios.

```javascript theme={null}
const { loadESLint } = require("eslint");

async function main() {
  const ESLintClass = await loadESLint();
  const eslint = new ESLintClass();
}
```

<Note>
  In most cases, you can import ESLint directly. The `loadESLint` function is mainly for backward compatibility with older versions.
</Note>

## Configuration API

ESLint also exports configuration helpers from `eslint/config`:

```javascript theme={null}
const { defineConfig, globalIgnores } = require("eslint/config");
```

* [defineConfig](/api/config/define-config) - Type-safe config definition helper
* [globalIgnores](/api/config/global-ignores) - Helper for global ignore patterns

## Basic Usage

<Tabs>
  <Tab title="Linting Files">
    ```javascript theme={null}
    const { ESLint } = require("eslint");

    async function lintFiles() {
      const eslint = new ESLint({
        overrideConfigFile: "eslint.config.js"
      });

      const results = await eslint.lintFiles(["src/**/*.js"]);
      const formatter = await eslint.loadFormatter("stylish");
      console.log(formatter.format(results));
    }

    lintFiles();
    ```
  </Tab>

  <Tab title="Linting Text">
    ```javascript theme={null}
    const { Linter } = require("eslint");

    const linter = new Linter();
    const messages = linter.verify(
      "var foo = 'bar';",
      { rules: { "no-var": "error" } }
    );

    console.log(messages);
    ```
  </Tab>
</Tabs>

## Version Information

You can access the ESLint version from both classes:

```javascript theme={null}
console.log(ESLint.version);  // e.g., "9.0.0"
console.log(Linter.version);  // e.g., "9.0.0"
```