https://github.com/vihanb/babel-plugin-loop-optimizer

Optimizes statements such as `forEach` and `map` to for loops.
https://github.com/vihanb/babel-plugin-loop-optimizer

babel-plugin

Last synced: 3 months ago
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Optimizes statements such as `forEach` and `map` to for loops.

• Host: GitHub
• URL: https://github.com/vihanb/babel-plugin-loop-optimizer
• Owner: vihanb
• License: mit
• Created: 2016-11-29T03:47:08.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2020-07-19T06:03:08.000Z (over 4 years ago)
• Last Synced: 2024-04-18T13:11:34.012Z (7 months ago)
• Topics: babel-plugin
• Language: JavaScript
• Size: 90.8 KB
• Stars: 74
• Watchers: 8
• Forks: 7
• Open Issues: 9
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-babel - loop-optimizer - Transforms `.forEach` and `.map` calls to for loops. 🔧 (Plugins / Optimization)

README

        
# babel-plugin-loop-optimizer

**WARNING:** This package is **unmaintained**. It probably still works but I am not able to maintain it. If anyone wishes to pick this up leave an issue and I can give access.

Also, that package aren't working with newest Babel (that have @babel namespace) right now.

Optimizes `.forEach`, `.every`, `.find`, `.map`, `.filter` statements to `for` stements

## Installation

```sh

$ npm install babel-plugin-loop-optimizer

```

## Usage

### Via `.babelrc` (Recommended)

**.babelrc**

```json

{

  "plugins": ["babel-plugin-loop-optimizer"]

}

```

### Via CLI

```sh

$ babel --plugins loop-optimizer script.js

```

### Via Node API

```js

require('babel').transform('code', {

  plugins: ['loop-optimizer']

});

```

## Bugs?

Now you may say "wait, wait, wait!" This optimizes on things that aren't just arrays! My `map#forEach` is optimized too! To fix this, add a comment that says `// O: KEEP` right before the line on which you use some optimized function. Examples:

```js

var m = new Map();

// loop-optimizer: KEEP

m.forEach(f)

```

or:

```js

var s = new Set();

// loop-optimizer: KEEP

for (var i = 0; i < 5; s.forEach(f)) {

    // ...

}

```

This is required since it is not possible to determine an object's type at compile-time.

Also, if you don't want reverse order, you can disable this (optimization) behavior by adding comment `// loop-optimizer: FORWARD` right before the line on which you use some optimized function. Example:

```js

let ar = [1, 2, 3]

// loop-optimizer: FORWARD

ar.forEach(console.log)

```

## Example

```js

function timesTwo(arr) {

	return arr.map(n => n * 2);

}

```

to:

```js

function timesTwo(arr) {

    let _a = arr;

    let _f = n => n * 2;

    let _r = [];

    for (let _i = _a.length; _i--;)

        _r.push(_f(_a[_i], _i, _a));

    return _r;

}

```

---

If you need any other help, don't hesitate to leave an issue