https://github.com/wildhoney/moggy

Miniature ~2kb library that brings immutability to existing prototype functions employing the principle of least astonishment.
https://github.com/wildhoney/moggy

functional immutability immutable prototype side-effect tuples

Last synced: 2 months ago
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Miniature ~2kb library that brings immutability to existing prototype functions employing the principle of least astonishment.

• Host: GitHub
• URL: https://github.com/wildhoney/moggy
• Owner: Wildhoney
• License: gpl-3.0
• Created: 2017-02-06T22:55:49.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2017-02-16T10:23:52.000Z (over 9 years ago)
• Last Synced: 2025-02-01T02:35:26.465Z (over 1 year ago)
• Topics: functional, immutability, immutable, prototype, side-effect, tuples
• Language: JavaScript
• Homepage:
• Size: 1.54 MB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
![Moggy](media/logo.png)

> *moggy → transmogrify → "transform in a surprising or magical manner."*


> Miniature ~2kb library that brings immutability to existing prototype functions employing the [principle of least astonishment](https://en.wikipedia.org/wiki/Principle_of_least_astonishment).

[![forthebadge](http://forthebadge.com/images/badges/contains-cat-gifs.svg)](http://forthebadge.com)

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## Getting Started

Moggy inspects the `prototype` of the value and creates an `object` that takes the functions from the prototype – it's therefore not easy to say *which* functions Moggy implements, since ECMAScript functions that mutate the value will respond with a tuple of `[sideEffect, returnValue]`, whereas functions that are already immutable in their nature will respond as-is.

```javascript

import m from 'moggy';

const a = m([1, 2, 3]);

const b = a.push(4); 

const c = a.pop();

console.log(a); // [1, 2, 3]

console.log(b); // [sideEffect = [1, 2, 3, 4], returnValue = 4]

console.log(c); // [sideEffect = [1, 2], returnValue = 3]

```

In such cases it's not always obvious which value you may require – that's why Moggy returns both as a tuple. In the case of `push` you're more likely to require `sideEffect`, however in `pop` you're more likely to require the `returnValue`.

Using destructuring it's easy to take what you need – ignoring what you don't need.

```javascript

import m from 'moggy';

const a = m([1, 2, 3]);

const [b] = a.push(4);

const [, c] = a.pop();

console.log(a); // [1, 2, 3]

console.log(b); // [1, 2, 3, 4]

console.log(c); // 3

```