What is the Syntax for Declaring Functions in JavaScript ?

Generally, in JavaScript, the function keyword is used to declare a variable. But, there are some more ways available in JavaScript that can be used to declare functions as explained below:

• Using function keyword: This is the most common way to declare functions in JavaScript by using the function keyword before the name of the function.
• Declaring anonymous functions: In this syntax the declared function has no name as it is assigned to a variable.
• Using arrow function: It is the shorter way of declaring a function in JavaScript using an arrow(=>) introduced in ES6.
• Using Function constructor: JavaScript provides us with a Function() constructor to declare functions.

Example: The below code declares functions in JavaScript using the above-discussed approaches.

Javascript

// Using function keyword
function GFG(){console.log("GeeksforGeeks");}
GFG();

// Anonymous function
const anonyFunc = function(){console.log("GFG");}
anonyFunc();

// Arrow function
const arrowFunc = () => {console.log("JavaScript");}
arrowFunc();

// Function constructor
const product = Function('num1', 'num2', 'return num1*num2');
console.log(product(3, 2));

Output

GeeksforGeeks
GFG
JavaScript
6