What is function* in JavaScript ?

The function* keyword defines a generator function, which allows you to control the iteration process explicitly. Generator functions can yield multiple values over time, pausing and resuming execution as needed.

Example: Here, generateSequence() is a generator function defined using the function* syntax. When called, it returns a generator object. The next() method of the generator object is used to iterate through the sequence of yielded values (1, 2, and 3), and each value is printed to the console.

Javascript

function* generateSequence() {
    yield 1;
    yield 2;
    yield 3;
}

let generator = generateSequence();

console.log(generator.next().value); // Output: 1
console.log(generator.next().value); // Output: 2
console.log(generator.next().value); // Output: 3

Output

1
2
3