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 are comprise the body of the function.

Below examples illustrate the function* expression in JavaScript:

Example 1:

Javascript

<script>
    // 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);
</script>

Output:

123 - Geeks

Example 2:

Javascript

<script>
    // 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);
    }
</script>

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