JavaScript function* expression

The function* is an inbuilt keyword in JavaScript which is used to define a generator function inside an expression.

Syntax:

function* [name]([param1[, param2[, ..., paramN]]]) {
   statements
}

Parameters: This function accepts the following parameter as mentioned above and described below:

• name: This parameter is the function name.
• paramN: This parameter is the name of an argument to be passed to the function.
• statements: These parameters comprise the body of the function.

Example 1: Below examples illustrate the function* expression in JavaScript:

Javascript

// Illustration of function* expression
// use of function* keyword
function* func() {
    yield 1;
    yield 2;
    yield 3;
    yield " - Geeks";
}

let obj = '';

// Function calling
for (const i of func()) {
    obj = obj + i;
}

// Output
console.log(obj);

Output

123 - Geeks

Example 2: Below examples illustrate the function* expression in JavaScript:

Javascript

// Illustration of function* expression
// use of function* keyword
function* func2(y) {
    yield y * y;
};

function* func1() {
    for (let i = 1; i < 6; i++) {
        yield* func2(i);
    }
};

// Function calling
for (const x of func1()) {

    // Output
    console.log(x);
};

Output

1
4
9
16
25

Supported Browsers:

The browsers supported by JavaScript function* expression are listed below:

• Google Chrome 49 and above
• Edge 12 and above
• Firefox 26 and above
• Opera 36 and above
• Safari 10 and above