babel-plugin-transform-for-of-as-array

babel-plugin-transform-for-of-as-array

Transform all for-of loops into the equivalent array for loop

Example

In

const array = [1, 2, 3];
for (const elm of array) {
  console.log(elm);
}

let item;
for ({ item } of array.map(item => ({ item }))) {
  console.log(item);
}

Out

const array = [1, 2, 3];

for (let _i = 0, _length = array.length; _i < _length; _i++) {
  const elm = array[_i];
  console.log(elm);
}

let item;
for (let _i2 = 0, _array$map = array.map(item => ({ item })), _length2 = _array$map.length; _i2 < _length2; _i2++) {
  ({ item } = _array$map[_i2]);

  console.log(item);
}

loose transformation

In addition to the normal transform, we also support a null-ish checking loose transform. Passing { loose: true } option into the plugin enables it:

In

const array = null;
for (const elm of array) {
  console.log(elm);
}

let item;
for ({ item } of array.map(item => ({ item }))) {
  console.log(item);
}

Out

const array = null;

for (let _i = 0, _length = array == null ? 0 : array.length; _i < _length; _i++) {
  const elm = array[_i];
  console.log(elm);
}

let item;
for (let _i2 = 0, _array$map = array.map(item => ({ item })), _length2 = _array$map == null ? 0 : _array$map.length; _i2 < _length2; _i2++) {
  ({ item } = _array$map[_i2]);

  console.log(item);
}

Installation

$ npm install babel-plugin-transform-for-of-as-array

Usage

Via .babelrc (Recommended)

.babelrc

{
  "plugins": ["transform-for-of-as-array"]
}

Via CLI

$ babel --plugins transform-for-of-as-array script.js

Via Node API

require("babel-core").transform("code", {
  plugins: ["transform-for-of-as-array"]
});