What is a Function? Simple Explanation with Examples

Source: Dev.to

What is a Function?

A function is a block of code that performs a specific task.
Instead of writing the same code repeatedly, you can write it once inside a function and reuse it whenever needed.

Example

function square(number) {
  return number * number;
}

• function is the keyword that defines a function.
• square is the function name.
• The parentheses contain parameters (in this case, number). If you need multiple parameters, separate them with commas.

Calling the Function

To execute the function, call it by its name:

let calculation = square(2); // => 4
console.log(calculation);    // 4

• square(2) passes the argument 2 to the parameter number.
• The function returns number * number, which is 2 * 2 = 4.
• The returned value is stored in the variable calculation and then logged to the console.

Reference

• MDN Web Docs – Functions