immutable updates methods

.md

Let's explore a few ways to do immutable updates in js. We'll start with this data:

var data = {
  foo: {
    bar: 1,
    baz: 2,
  }
};

Object.assign is part of es6, it's ugly but it's standard.

var updated = Object.assign(
  {},
  data,
  {
    foo: Object.assign(
      {},
      data.foo,
      {bar: 'updated'}
    )
  }
);

Object spread gives nicer code, but it's experimental syntax

var updated = {
  ...data,
  foo: {
    ...data.foo,
    bar: 'updated'  
  }
};

The react updates addon gives a decent syntax for deep updates. It's very flexible but still a bit clunky.

var update = require('react-addons-update');
var updated = update(data, {
  foo: {
    bar: {$set: 'updated'}
  }
});

imset is less powerful than the previous in that it can only perform one update at a time. It has, in my opinion, the best syntax, and only requires es6.

It's currently missing some tests, so I wouldn't recommend using it yet.

var imset = require('imset');
var updated = imset`${data}.foo.bar = 'updated'`;