Japanese version. The function data type in JavaScript is used to define reusable blocks of code. Using functions allows you to call the same code in multiple places without repeating the same code over and over again. Code Example Here’s an example of defining a function to square a number using the function keyword: This function takes an argument num and returns the square of that argument. You can call the function like this: In this example, we’re calling the square() function, passing in 5 as the argument, and receiving 25 as the return value. Functions provide flexibility to reuse code as needed and reduce code duplication. Functions are used … Continue reading function(JavaScript Variable data type)