Adding values to collections

The two main collection types on which we'll call persistent change methods are lists and maps. When you call a method to add a new value to a collection, you have to store the result somewhere because persistent changes only create data; they never destroy data.

Pushing values to lists

You can push a new value onto a list using the push() method, as follows:

const myList = List.of(1, 2, 3);
const myChangedList = myList.push(4);

console.log('myList', myList.toJS());
// -> myList [ 1, 2, 3 ]
console.log('myChangedList', myChangedList.toJS());
// -> myChangedList [ 1, 2, 3, 4 ]

The end result of calling push(4) is a new list. If you want to make use of this list, you have...