mewt
Immutability in under one kilobyte
Made with
$set and $unset for objects and arrays.
Install
npm install --save mewtyarn add mewtImport
// ES2015
import immutable from 'mewt'// CommonJS
var immutable = require('mewt')Usage
Create an immutable instance from a JavaScript array or object.
Both objects and arrays have the $set and $unset methods.
const immutableArray = immutable([])
const immutableObject = immutable({})
immutableArray[0] = 'Van Morrison' //=> Error "array is immutable"
immutableObject.name = 'Van Morrison' //=> Error "object is immutable"Array
Use $set and $unset to create new array with applied change.
Use all array instance methods as usual, however those that would normally return a single non-array value (pop, push, shift, unshift) will return an array containing the value and a new array (see part 2 in example below).
const arr = immutable([])
// 1. all array instance methods are available
const arr1 = arr.concat('bubble')
console.log(arr1) //=> ['bubble']
console.log(arr1 === arr) //=> false
// 2. methods with non-array return value (push, pop, shift, unshift)
// also return new array, accessible via destructuring
const [val, arr2] = arr1.pop()
console.log(val) //=> 'bubble'
console.log(arr2) //=> []
console.log(arr2 === arr1) //=> false
// 3. use $set and $unset to get new array with changes
const arr3 = arr2.$set(0, 'Iggy Pop')
console.log(arr3) //=> ['Iggy Pop']
console.log(arr3 === arr2) //=> falseObject
Use $set and $unset to create new object with applied change.
const obj = immutable({})
// 1. properties are added/updated using `$set`
const obj1 = obj.$set('album', 'Hunky Dory')
console.log(obj1) //=> {album: 'Hunky Dory'}
console.log(obj1 === obj) //=> false
// 2. properties are deleted using `$unset`
const obj2 = obj1.$unset('album')
console.log(obj2) //=> {}
console.log(obj2 === obj1) //=> falseContributors
mewt has received contributions from these wonderful people:
Balรกzs รdes, Scott Humphries, Michael J. Ryan, Jamie Curtis
Contributing
All pull requests and issues welcome!
If you're not sure how, check out the great video tutorials on egghead.io!