JavaScript | Generator.prototype.next() Method

The Generator.prototype.next() method is an inbuilt method in JavaScript which is used to return an object with two properties done and value.

Syntax:

gen.next( value );

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

  • value: This parameter holds the value to be sent to the generator.

Return value: This method returns an object containing two properties:

  1. done: It has the value
    • true – for the iterator which past the end of the iterated sequence.
    • false – for the iterator which are able to produce the next value in the sequence.
  2. value: It contains any JavaScript value which is returned by the iterator.

Below examples illustrate the Generator.prototype.next() method in JavaScript:



Example 1:

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function* GFG() { 
  yield "GeeksforGeeks";
  yield "JavaScript";
  yield "Generator.prototype.next()";
}
  
const geek = GFG(); 
console.log(geek.next());      
console.log(geek.next());      
console.log(geek.next());     
console.log(geek.next());  

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Output:


Object { value: "GeeksforGeeks", done: false }
Object { value: "JavaScript", done: false }
Object { value: "Generator.prototype.next()", done: false }
Object { value: undefined, done: true }



Example 2:













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function* GFG(len, list) { 


    let result = []; 


    let val = 0; 


    


    while (val < list.length) { 


        result = []; 


        let i = val 


        while(i < val + len) 


          { 


            if (list[i]) { 


                result.push(list[i]); 


            } 


           i+=1 


        } 


    


        yield result; 


        val += len; 


    } 


} 


list = [ 


    'geeks1','geeks2','geeks3', 


    'geeks4','geeks5','geeks6', 


    'geeks7','geeks8','geeks9', 


    'geeks10','geeks11'


]; 


  


var geek = GFG(4, list);               


    


document.writeln(geek.next().value+"<br>");       


document.writeln(geek.next().value+"<br>");     


document.writeln(geek.next().value+"<br>");     


document.writeln(geek.next().value+"<br>"); 



















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Output:


geeks1,geeks2,geeks3,geeks4
geeks5,geeks6,geeks7,geeks8
geeks9,geeks10,geeks11
undefined


Supported Browsers: The browsers supported by Generator.prototype.next() method are listed below:


    

  • Google Chrome
    • 

  • Firefox
    • 

  • Opera
    • 

  • Safari
    • 

  • Edge
    • 



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