@babel/parser

What is @babel/parser?

The @babel/parser package is a JavaScript parser that allows you to convert ECMAScript 2015+ code into a parse tree. This package is part of the Babel toolchain and is primarily used for transforming JavaScript code. It provides a flexible and extensible framework for parsing modern JavaScript syntax, enabling developers to analyze, understand, and manipulate the code structure.

What are @babel/parser's main functionalities?

Parsing JavaScript

This feature allows you to parse JavaScript code into an abstract syntax tree (AST). The code sample demonstrates how to parse a simple piece of JavaScript code, specifying the source type and enabling plugins for JSX and TypeScript support.

const babelParser = require('@babel/parser');
const code = 'let x = 1;';
const ast = babelParser.parse(code, {
  sourceType: 'module',
  plugins: [
    'jsx',
    'typescript'
  ]
});

Using Plugins for Syntax Support

The @babel/parser package supports various plugins to extend its parsing capabilities to include newer JavaScript syntax and experimental features. This example shows how to enable the 'asyncGenerators' and 'classProperties' plugins to parse code using these features.

const astWithPlugins = babelParser.parse(code, {
  plugins: [
    'asyncGenerators',
    'classProperties'
  ]
});

Other packages similar to @babel/parser

acorn

Acorn is a lightweight, fast JavaScript parser written in JavaScript. It aims to achieve similar goals as @babel/parser, providing an AST for source code. However, Acorn focuses more on speed and a smaller footprint, making it a good choice for environments where these factors are critical.

esprima

Esprima is another popular JavaScript parser that supports ECMAScript 3, 5, 2015, 2016, 2017, and 2018 standards. It is used by many tools and frameworks for static analysis and code manipulation. Compared to @babel/parser, Esprima offers a more stable and standardized parsing solution but might not be as flexible in terms of plugin support and experimental syntax.

README

@babel/parser

A JavaScript parser

See our website @babel/parser for more information or the issues associated with this package.

Install

Using npm:

npm install --save-dev @babel/parser

or using yarn:

yarn add @babel/parser --dev

Changelog

v7.26.3 (2024-12-04)

:bug: Bug Fix

• babel-generator
  • #16958 [preserveFormat] force semicolons when invalidating ASI (@nicolo-ribaudo)

:house: Internal

• babel-helper-builder-binary-assignment-operator-visitor, babel-plugin-transform-exponentiation-operator
  • #16895 Remove helper-builder-binary-assignment-operator-visitor (@nicolo-ribaudo)

:running_woman: Performance

• babel-generator
  • #16959 perf: Reduce the use of temporary objects (@liuxingbaoyu)
• babel-traverse
  • #16923 perf: Improve scope information collection performance (@liuxingbaoyu)
  • #16964 perf: Avoid repeated traversal when creating scope (@liuxingbaoyu)
• babel-plugin-transform-modules-commonjs
  • #16954 perf: Remove use of simplifyAccess (@liuxingbaoyu)