Four Different Ways to Write Functions in Javascript

Functions are the basic building blocks of the Javascript. A function in Javascript is a code block that performs a specific task or set of tasks.

There are basically 4 (four) different ways we can define functions in Javascript.

Function Declaration
Function Expression
Arrow Function Expression
Concise Arrow Function Expression

// Function Declaration
function square(x) {
  return x * x;
}

// Function Expression
const square = function (x) {
  return x * x;
};

// Arrow Function Expression
const square = (x) => {
  return x * x;
};

// Concise Arrow Function Expression
const square = (x) => x * x;

If you prefer you can take a look at the video tutorial,