state-update-helper

Easily mutate an object

Setup via NPM

npm install state-update-helper --save

Usage

The state-update-helper package provides the udpate() function, which can be used to make a copy of a an object, changing only a few fields. Here is a basic example of a call to update()

import update from 'state-update-helper'

const obj = {
    name: "John Doe",
    age: 40,
    profession: "programmer"
}

const newObj = update(obj, {
    name: { set: "Jane Doe" },
    age: { $add: 2 }
}); // {name: "Jane Doe", age: 42, profession: "programmer"}

// obj has not changed

Update types

• {set: any} overwrites existing field value
• {inc: Number} adds number value to field
• {push: any} pushes value onto array
• {concat: array} concatenates given array with existing one (can be used to push multiple vlaues)