I've recently come across the const keyword in JavaScript. From what I can tell, it is used to create immutable variables, and I've tested to ensure that it cannot be redefined (in Node.js):  const x = 'const'; const x = 'not-co...

Why should objects in Redux be immutable? I know that some frameworks such as Angular2 will use onPush and can take advantage of immutability to compare states of views for faster rendering, but I am wondering if there are other reasons as Redux is f...

I have an issue with updating the immutable redux and quite nested data. Here's an example of my data structure and what I want to change. If anyone could show me the pattern of accessing this update using ES6 and spread operator I would be thank...

I wonder how to contact array that is immutable. Lets imagine I start with array list = [4,1], and then I receive array from action response like so items = [5,2,6]. How do I concant arrays that the result is [4,1,5,2,6] and that operation is not mut...

I'm still learning React and working on coding John Conway's Game of Life. I have created a game board for the game using a 2D array in state. I have this 2D array stored in state in my App.js. I also have two functional components, Gameboard...

Suppose I have the following Records defined using Immutable.js:  var Address = Immutable.Record({street: '', city: '', zip: ''}); var User = Immutable.Record({name: '', address: new Address()});   How do I convert pla...

Is there any elegant way of removing an object from an array which is part of an array? I have been working with React and Redux for a while now but get stuck several hours everytime I have to remove or insert data without mutating the state.  The re...

I want to have a function which returns an Array, but I want the returned Array to be readonly, so I should get a warning/error when I try to change its contents.  function getList(): readonly number[] {    return [1,2,3]; }   const list = getList();...

This question might fall a little on the side of a "best practice" question, but please bear with me.  Here is a portion of my state:  this.state = {   typeElements: {     headers: [         {           name: "h1",           size: 70,...

Let's say we have an immutable object that is created using Facebook's great Immutable.js. I want to compare two lists that were produced using .map or .filter out of single source and make sure they are equal. It seems to me, that when using...