Babel Comment Extractor

Common errors

• TypeError: (0, _babelExtractComments.default) is not a function

  cause Attempting to use an ES Module `import` statement for a CommonJS-only package, trying to access a default export that doesn't exist in the ES Module wrapper.
  fix Change your import statement to `const extract = require('babel-extract-comments');`

• SyntaxError: Unexpected token

  cause The input JavaScript string or file contains syntax features (e.g., optional chaining `?.`, nullish coalescing `??`, private class fields `#`) that are not supported by the older Babel parser version used by this library.
  fix Either refactor the JavaScript code to use older syntax, or switch to a different, actively maintained comment extraction library that supports modern ECMAScript features.

Warnings

• breaking This package is CommonJS-only. Attempting to import it using ES Module syntax (`import ... from '...'`) in an ESM context will result in a runtime error.
  Fix: Always use `const extract = require('babel-extract-comments');` for importing the library.
• gotcha The library was last published in 2018 and uses an older version of Babel's parser (Babylon). It may not correctly parse or may throw errors when encountering modern JavaScript syntax (e.g., optional chaining, nullish coalescing, private class fields, top-level await) introduced after ES2017.
  Fix: For parsing modern JavaScript, consider using a more actively maintained parser or comment extraction library based on a current Babel version or alternative parsers like `@babel/parser` directly, or `extract-comments` with a modern extractor plugin.
• deprecated The project appears to be abandoned, with no updates or new versions released since 2018. This implies a lack of support for bug fixes, security patches, or new feature development, making it a risky dependency for new projects or those requiring long-term stability.
  Fix: Evaluate alternatives if your project requires active maintenance, support for modern JavaScript, or strict security posture. If used, pin the version exactly to avoid unexpected issues.

Install

• npm install babel-extract-comments npm
• yarn add babel-extract-comments yarn
• pnpm add babel-extract-comments pnpm

Imports

• extract
  wrong:

  import extract from 'babel-extract-comments';

  correct:

  const extract = require('babel-extract-comments');

  This package is CommonJS-only and does not support ESM imports. Attempting ESM import will result in a runtime error.
• extract.file
  wrong:

  import { file } from 'babel-extract-comments';

  correct:

  const extract = require('babel-extract-comments');
  const commentsFromFile = extract.file('./path/to/my-file.js');

  The `.file` method is accessed as a property of the default CommonJS import. Direct named ESM imports are not supported.

Quickstart

Demonstrates extracting comments from both a JavaScript string and a file using the `extract` function and its `.file` method. It showcases different comment types and the structure of the returned comment objects.

const extract = require('babel-extract-comments');
const fs = require('fs');

const jsString = `
// This is a line comment
/**
 * This is a block comment.
 * It can span multiple lines.
 */
const myVariable = 123; // Inline comment

/* Another block comment */
function myFunction() {
  /*
   * Multi-line
   * function comment
   */
  console.log('Hello');
}
`;

// Extract comments from a string
const stringComments = extract(jsString);
console.log('Comments from string:', JSON.stringify(stringComments, null, 2));

// Create a dummy file for .file method demonstration
const filePath = './temp-script.js';
fs.writeFileSync(filePath, jsString);

// Extract comments from a file
const fileComments = extract.file(filePath);
console.log('\nComments from file:', JSON.stringify(fileComments, null, 2));

// Clean up the dummy file
fs.unlinkSync(filePath);