Creating singleton in javascript

Singleton pattern is used to make sure only one object of class is created across the whole application.

In this article i am going to describe how we can achieve singleton in javascript es6. There are multiple ways to achieve this but the one which i am going to write is very simple & clean.

Check out the below code -

class Person {
    constructor() {
        if (this.instance) {
            return this.instance;
        } else {
            Person.prototype.instance = this;
        }
    }
    getName() {
        console.log(this.name);
    }
    setName(val) {
        this.name = val;
    }
}
const person1 = new Person();
person1.setName("ujjwal");
person1.getName(); // value will be ujjwal
const person2 = new Person();
person2.setName("ujjwal gupta");
// here we are trying to get value from person1 instance but since the class Person is singleton. It will return value from last set.
person1.getName(); // value will be again ujjwal gupta

Here we are using prototype to ensure - we have only one value of instance for whole class.

Hope you find this article useful. Thanks for reading guys!.