Working with Immer

We are going to take a look at another popular immutability library. The library is known as Immer, and it can be installed using the following npm command:

npm install immer

Immer allows us to define immutable classes using the readonly access modifier. This means that we can also create instances of our classes using a standard class constructor:

import produce from "immer";

class Street {

    public readonly num: number;
    public readonly name: string;

    public constructor(num: number, name: string) {
        this.num = num;
        this.name = name;
    }

}

class Address {

    public readonly city: string;
    public readonly street: Street;

    public constructor(city: string, street: Street) {
        this.city = city;
        this.street = street;
    }

}

const address = new Address(
    "London",
    new Street(1, "rathbone square")
);