README

object-path-immutable-rowrowrowrow

This repo is based on https://github.com/mariocasciaro/object-path-immutable with added features. Namely the following:

Get method is not imported from https://github.com/mariocasciaro/object-path.
Support performing some methods recursively on all items in a deepset array.
Adds an ensureExists method which does not mutate the source if the target property is set.

Please checkout mariocasciaro's repo for more information.

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.

Please see the basis for this repo

object-path-immutable

Install

npm install object-path-immutable-rowrowrowrow --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)

const obj = {
  a: {
    b: 'c',
    c: ['d', 'f']
  }
}

const newObj = immutable.set(obj, 'a.b', 'f')
// {
//   a: {
//     b: 'f',
//     c: ['d', 'f']
//   }
// }

// obj !== newObj
// obj.a !== newObj.a
// obj.a.b !== newObj.a.b

// However:
// 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.

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

API

// Premises

const obj = {
  a: {
    b: 'f',
    c: ['d', 'f'],
    'MAP': [
      {
        g: 'h1',
        i: 'j1'
      },
      {
        g: 'h2',
        i: 'j2'
      },
    ]
  }
};

import immutable from 'object-path-immutable-rowrowrowrow'

get (initialObject, path, defaultValue, matchThenMap)

Return an object property or array of object properties.

Path can be either a string or an array.
matchThenMap is an array of keys that once matched in the object will propogate the path, defaultValue, and matchThenMap to all array values returning an array of values.

const existingObject1 = immutable.get(obj, 'a.MAP.g', 'f',['MAP'])

// ['h1','h2']

const existingObject2 = immutable.get(obj, ['a', 'MAP','i'], 'f',['MAP'])

import * as immutable from 'object-path-immutable'

set (initialObject, path, value)

Changes an object property.

Path can be either a string or an array.

const newObj1 = immutable.set(obj, 'a.b', 'f')
const newObj2 = immutable.set(obj, ['a', 'b'], 'f')

// {
//   a: {
//     b: 'f',
//     c: ['d', 'f']
//   }
// }

// Note that if the path is specified as a string, numbers are automatically interpreted as array indexes.

const newObj = immutable.set(obj, 'a.c.1', 'fooo')
// {
//   a: {
//     b: 'f',
//     c: ['d', 'fooo']
//   }
// }

update (initialObject, path, updater)

Updates an object property.

const obj = {
  a: {
    b: 1
  }
}

const newObj = immutable.update(obj, ['a', 'b'], v => v + 1)

// {
//   a: {
//     b: 2,
//   }
// }

push (initialObject, path, value)

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

const newObj = immutable.push(obj, 'a.d', 'f')
// {
//   a: {
//     b: 'f',
//     c: ['d', 'f'],
//     d: ['f']
//   }
// }

del (initialObject, path)

Deletes a property.

const newObj = immutable.del(obj, 'a.c')
// {
//   a: {
//     b: 'f'
//   }
// }

Can also delete a deep array item using splice

const newObj = immutable.del(obj, 'a.c.0')
// {
//   a: {
//     b: 'f',
//     c: ['f']
//   }
// }

assign (initialObject, path, payload)

Shallow copy properties.

const newObj = immutable.assign(obj, 'a', { b: 'f', g: 'h' })
// {
//   a: {
//     b: 'f',
//     c: ['d, 'f'],
//     g: 'h'
//   }
// }

insert (initialObject, path, payload, position)

Insert property at the specific array index.

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

merge (initialObject, path, value)

Deep merge properties.

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

Getters (not available in wrap mode)

get (object, path, defaultValue)

Not mported from object-path so as to allow recursive get on deepset arrays.

Usage no npm install needed!