@babel/plugin-transform-regenerator

What is @babel/plugin-transform-regenerator?

The @babel/plugin-transform-regenerator package is a Babel plugin that enables the transformation of generator functions and async functions into ES5-compatible JavaScript code using the regenerator runtime. It allows developers to use these modern features in environments that do not natively support them.

What are @babel/plugin-transform-regenerator's main functionalities?

Transformation of generator functions

This plugin transforms generator functions into ES5 code by converting the generator syntax into a state machine that is compatible with older JavaScript engines.

function* gen() { yield 1; yield 2; yield 3; }

Transformation of async functions

It also transforms async functions into generator functions and then applies the generator function transformation to ensure compatibility with environments that do not support async/await syntax.

async function foo() { await someAsyncFunction(); }

Other packages similar to @babel/plugin-transform-regenerator

regenerator-runtime

The regenerator-runtime package provides the runtime needed to support the generator functions in environments that do not natively support them. It is often used in conjunction with @babel/plugin-transform-regenerator, which handles the syntax transformation.

babel-plugin-transform-async-to-generator

This package is similar to @babel/plugin-transform-regenerator in that it transforms async functions into generator functions. However, it focuses solely on async functions and does not handle generator functions.

fast-async

fast-async is a Babel plugin that transforms async/await functions into ES5-compatible code using Promises instead of generators. It provides an alternative approach to handling async functions and can be faster than regenerator-based transformations.

README

@babel/plugin-transform-regenerator

Transform async/generator functions with regenerator

Example

In

function* a() {
  yield 1;
}

Out

var _marked = [a].map(regeneratorRuntime.mark);

function a() {
  return regeneratorRuntime.wrap(function a$(_context) {
    while (1) {
      switch (_context.prev = _context.next) {
        case 0:
          _context.next = 2;
          return 1;

        case 2:
        case "end":
          return _context.stop();
      }
    }
  }, _marked[0], this);
}

Installation

npm install --save-dev @babel/plugin-transform-regenerator

Usage

Via .babelrc (Recommended)

Without options:

{
  "plugins": ["@babel/plugin-transform-regenerator"]
}

With options:

name	default value
asyncGenerators	true
generators	true
async	true

{
  "plugins": [
    ["@babel/plugin-transform-regenerator", {
      "asyncGenerators": false,
      "generators": false,
      "async": false
    }]
  ]
}

Via CLI

babel --plugins @babel/plugin-transform-regenerator script.js

Via Node API

require("@babel/core").transform("code", {
  plugins: ["@babel/plugin-transform-regenerator"]
});