JavaScript How to create your own functions using variable argumentsJavaScript

This article explains how to define your own functions using variable arguments in JavaScript.

I want to create my own function using variable arguments, but how should I define it?

To create a custom function with variable arguments, use the arguments object to get the number of arguments.

You can also use the rest parameter to treat arguments as arrays.

Method using arguments object

The arguments object is an object for getting the arguments defined within the function.

You can use the arguments object to get the number and values ​​of arguments. This method allows you to handle variable-length arguments.

Below is a sample code of a self-made function using arguments object.

function sum() {
  let total = 0;
  for (let i = 0; i < arguments.length; i++) {
    total += arguments[i];
  }
  return total;
}

console.log(sum(1, 2, 3, 4)); // 10
console.log(sum(5, 6, 7, 8, 9)); // 35

How to use rest parameters

The rest parameter can treat arguments as an array. This method allows you to handle variable-length arguments. The rest parameter is defined using a three-dot leader (…).

Below is a sample code of a self-made function using rest parameters.

function sum(...numbers) {
  let total = 0;
  for (let i = 0; i < numbers.length; i++) {
    total += numbers[i];
  }
  return total;
}

console.log(sum(1, 2, 3, 4)); // 10
console.log(sum(5, 6, 7, 8, 9)); // 35

Summary of this article

We explained how to define a self-made function using variable arguments.

When creating JavaScript functions, if you want to handle variable-length arguments, try using the arguments object or rest parameter. By using these, you can create more efficient functions.

Now you know how to use both the arguments object and the rest parameter!

Try using different methods depending on the method you want to use.