JavaScript Generator() Constructor

In JavaScript, there is no particular Generator() constructor but instead, we can use generator function declaration to construct a Generator object which is iterable as the Generator object is a subclass of the Iterable class. Generators are usually used to create functions that can be exited and re-entered.

Syntax:

function* gen(){
    // Sample Code
}
let example = gen();

Example 1: This example creates a generator object.

Javascript

function* gen(){
        let i = "a"
        yield i;
        yield i+"b";
    }

let example  = gen();

console.log(typeof(example))
console.log(example.next().value);
console.log(example.next().value);

Output: When we check the type of example we get the object as output as there is no inbuilt Generator object

object
a
ab

Example 2: This example creates an infinite generator object.

Javascript

function* gen(){
    let i = 123
    while(true){
        yield i++;
    }
}

let example  = gen();

for(let i = 0; i<5; i++) {
    console.log(example.next().value);
}

Output: We can iterate this generator function as much as we want as it will always remain true.

123
124
125
126
127

Supported Browsers:

• Chrome
• Edge 
• Firefox
• Opera
• Safari

We have a complete list of JavaScript Generator methods, to check those please go through, the JavaScript Generator Reference article