JavaScript Generator Reference
Last Updated :
25 May, 2023
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.
Javascript
function * nextNatural() {
let naturalNumber = 1;
while ( true ) {
yield naturalNumber++;
}
}
let gen = nextNatural();
for (let i = 0; i < 10; i++) {
console.log(gen.next().value)
}
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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.
Constructor |
Description |
Example |
Generator |
It is not available globally. Instances of Generator returned from generator functions. |
|
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.
Instance Properties |
Description |
Example |
constructor |
Return the generator constructor function for the object. |
|
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.
Instance Methods |
Description |
Example |
next() |
Return an object with two properties done and value. |
|
return() |
Return the given value and finishes the generator. |
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throw() |
The execution of a generator by throwing an error into it. |
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