JavaScript rest operator

The rest operator (Rest parameter… ) instructs the computer to add whatever arguments) supplied by the user into an array. The rest parameter syntax allows a function to accept an indefinite number of arguments as an array.

Triple dots… is the rest parameter. Rest syntax looks exactly like spread syntax.

function functionname(...parameters)  
{
   statement;
}

A simple example code calls a function with any number of arguments and then accesses those excess arguments as an array.

<!DOCTYPE html>
<html>
<body>

<script>
   function addAll(...num){
    let sum = 0;
    for(let i of num){
      sum+=i;
    }
    return sum;
  }
  console.log(addAll(1,2)); 
  console.log(addAll(1,2,3)); 
  console.log(addAll(1,2,3,4,5)); 

</script>

</body>
</html>

Output:

In the above example, the rest operator is used to gather all the arguments passed to the sum() function into an array called numbers. This makes it possible to handle an arbitrary number of arguments and calculate their sum.

Use rest to enclose the rest of specific user-supplied values into an array:

<script>
   function myBio(firstName, lastName, ...otherInfo) { 
    return otherInfo;
  }

  var res = myBio("John", "wick", "is a", "Web Developer", "in EyeHunts");
  console.log(res)

</script>

Output: [ “is a”, “Web Developer”, “in EyeHunts” ]

Do comment if you have any doubts or suggestions on this JS Rest topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version

JavaScript rest operator | Rest parameter