@babel/generator

What is @babel/generator?

The @babel/generator package is a part of the Babel toolchain that is responsible for generating code from an Abstract Syntax Tree (AST). It takes an AST as input and turns it into code with source maps, if desired. This is particularly useful when you want to transform code using Babel and then generate the transformed code.

What are @babel/generator's main functionalities?

Code Generation from AST

This feature allows you to generate code from an AST. The code sample demonstrates parsing a piece of code into an AST and then generating the code back from the AST.

const { parse } = require('@babel/parser');
const generate = require('@babel/generator').default;
const code = 'let a = 1;';
const ast = parse(code);
const output = generate(ast, {}, code);
console.log(output.code);

Source Map Support

This feature enables the generation of source maps along with the generated code. The code sample shows how to generate a source map for the code that is being generated from an AST.

const { parse } = require('@babel/parser');
const generate = require('@babel/generator').default;
const code = 'let a = 1;';
const ast = parse(code);
const output = generate(ast, { sourceMaps: true }, code);
console.log(output.map);

Other packages similar to @babel/generator

escodegen

Escodegen is an ECMAScript code generator that takes an AST and converts it back into code. It is similar to @babel/generator but does not provide the same level of integration with the Babel ecosystem.

recast

Recast is a JavaScript AST tool that allows you to parse, visit, and transform the nodes of your AST, and then regenerate JavaScript code. It preserves the original formatting as much as possible and can be used in conjunction with Babel.

astring

Astring is a tiny and fast JavaScript code generator from an ESTree-compliant AST. It is smaller and may be faster than @babel/generator but lacks the extensive plugin system and integrations that Babel offers.

README

@babel/generator

Turns an AST into code.

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

Install

Using npm:

npm install --save-dev @babel/generator

or using yarn:

yarn add @babel/generator --dev

Changelog

v7.25.7 (2024-10-02)

:bug: Bug Fix

• babel-helper-validator-identifier
  • #16825 fix: update identifier to unicode 16 (@JLHwung)
• babel-traverse
  • #16814 fix: issue with node path keys updated on unrelated paths (@DylanPiercey)
• babel-plugin-transform-classes
  • #16797 Use an inclusion rather than exclusion list for super() check (@nicolo-ribaudo)
• babel-generator
  • #16788 Fix printing of TS infer in compact mode (@nicolo-ribaudo)
  • #16785 Print TS type annotations for destructuring in assignment pattern (@nicolo-ribaudo)
  • #16778 Respect [no LineTerminator here] after nodes (@nicolo-ribaudo)

:nail_care: Polish

• babel-types
  • #16852 Add deprecated JSDOC for fields (@liuxingbaoyu)

:house: Internal

• babel-core
  • #16820 Allow sync loading of ESM when --experimental-require-module (@nicolo-ribaudo)
• babel-helper-compilation-targets, babel-helper-plugin-utils, babel-preset-env
  • #16858 Add browserslist config to external dependency (@JLHwung)
• babel-plugin-proposal-destructuring-private, babel-plugin-syntax-decimal, babel-plugin-syntax-import-reflection, babel-standalone
  • #16809 Archive syntax-import-reflection and syntax-decimal (@nicolo-ribaudo)
• babel-generator
  • #16779 Simplify logic for [no LineTerminator here] before nodes (@nicolo-ribaudo)

:running_woman: Performance

• babel-plugin-transform-typescript
  • #16875 perf: Avoid extra cloning of namespaces (@liuxingbaoyu)
• babel-types
  • #16842 perf: Improve @babel/types builders (@liuxingbaoyu)
  • #16828 Only access BABEL_TYPES_8_BREAKING at startup (@nicolo-ribaudo)