object-path-immutable

Tiny JS library to modify deep object properties without modifying the original object (immutability). Works great with React (especially when using setState()) and Redux (inside a reducer).

This can be seen as a simpler and more intuitive alternative to the React Immutability Helpers and Immutable.js.

Changelog

View Changelog

Install

npm install object-path-immutable --save

Quick usage

The following, sets a property without modifying the original object. It will minimize the number of clones down the line. The resulting object is just a plain JS object literal, so be warned that it will not be protected against property mutations (like Immutable.js)

1const obj = {
2  a: {
3    b: 'c',
4    c: ['d', 'f']
5  }
6}
7
8const newObj = immutable.set(obj, 'a.b', 'f')
9// {
10//   a: {
11//     b: 'f',
12//     c: ['d', 'f']
13//   }
14// }
15
16// obj !== newObj
17// obj.a !== newObj.a
18// obj.a.b !== newObj.a.b
19
20// However:
21// obj.a.c === newObj.a.c

Wrap mode

You can also chain the api's and call value() at the end to retrieve the resulting object.

1const newObj = immutable.wrap(obj).set('a.b', 'f').del('a.c.0').value()

API

1// Premises
2
3const obj = {
4  a: {
5    b: 'c',
6    c: ['d', 'f']
7  }
8}
9
10import * as immutable from 'object-path-immutable'

set (initialObject, path, value)

Changes an object property.

• Path can be either a string or an array.

1const newObj1 = immutable.set(obj, 'a.b', 'f')
2const newObj2 = immutable.set(obj, ['a', 'b'], 'f')
3
4// {
5//   a: {
6//     b: 'f',
7//     c: ['d', 'f']
8//   }
9// }
10
11// Note that if the path is specified as a string, numbers are automatically interpreted as array indexes.
12
13const newObj = immutable.set(obj, 'a.c.1', 'fooo')
14// {
15//   a: {
16//     b: 'f',
17//     c: ['d', 'fooo']
18//   }
19// }

update (initialObject, path, updater)

Updates an object property.

1const obj = {
2  a: {
3    b: 1
4  }
5}
6
7const newObj = immutable.update(obj, ['a', 'b'], v => v + 1)
8
9// {
10//   a: {
11//     b: 2,
12//   }
13// }

push (initialObject, path, value)

Push into a deep array (it will create intermediate objects/arrays if necessary).

1const newObj = immutable.push(obj, 'a.d', 'f')
2// {
3//   a: {
4//     b: 'f',
5//     c: ['d', 'f'],
6//     d: ['f']
7//   }
8// }

del (initialObject, path)

Deletes a property.

1const newObj = immutable.del(obj, 'a.c')
2// {
3//   a: {
4//     b: 'f'
5//   }
6// }

Can also delete a deep array item using splice

1const newObj = immutable.del(obj, 'a.c.0')
2// {
3//   a: {
4//     b: 'f',
5//     c: ['f']
6//   }
7// }

assign (initialObject, path, payload)

Shallow copy properties.

1const newObj = immutable.assign(obj, 'a', { b: 'f', g: 'h' })
2// {
3//   a: {
4//     b: 'f',
5//     c: ['d, 'f'],
6//     g: 'h'
7//   }
8// }

insert (initialObject, path, payload, position)

Insert property at the specific array index.

1const newObj = immutable.insert(obj, 'a.c', 'k', 1)
2// var obj = {
3//   a: {
4//     b: 'c',
5//     c: ['d, 'k' 'f'],
6//   }
7// }

merge (initialObject, path, value)

Deep merge properties.

1const newObj = immutable.merge(obj, 'a.c', {b: 'd'})

Getters (not available in wrap mode)

get (object, path, defaultValue)

Retrieve a deep object property. Imported from object-path for convenience.

Equivalent library with side effects

object-path