JavaScript Generator Reference

JavaScript Generator is used to allow us to define an iterative algorithm by writing a single function whose execution is not continuous.

Generator Constructor & Generator Objects

• Generator() Constructor: A generator constructor is defined as a normal function, but whenever it needs to generate a value, it does so with the yield keyword rather than return.
• Generator Object: Generator functions return a generator object. Generator objects are used either by calling the next method on the generator object or using the generator object in a “for of” loop.

Syntax:

// An example of the generator function
function* gen(){
    yield 1;
    yield 2;
    ...
    ...
}

Example: Below is an example code to print infinite series of natural numbers using a simple generator.

function* nextNatural() {
    let naturalNumber = 1;

    // Infinite Generation
    while (true) {
        yield naturalNumber++;
    }
}

// Calling the Generate Function
let gen = nextNatural();

// Loop to print the first
// 10 Generated number
for (let i = 0; i < 10; i++) {

    // Generating Next Number
    console.log(gen.next().value)
}

Output:

1    
2
3
4
5
6
7
8
9
10

The complete list of JavaScript Generators are listed below.

JavaScript Generator Constructor: In JavaScript, a constructor gets called when an object is created using the new keyword.

JavaScript Generator Properties: A JavaScript property is a member of an object that associates a key with a value.

Instance Property: An instance property is a property that has a new copy for every new instance of the class.

JavaScript Generator Methods: JavaScript methods are actions that can be performed on objects.

• Instance Method: If the method is called on an instance of a generator then it is called an instance method.