Dhananjay Kumar

Simplifying function expressions and the function statement in JavaScript

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In JavaScript, a function can be created in three possible ways:

Function as an expression
Function as a statement
Arrow functions

In this post, we will learn about function expressions and the function statement.

Consider the following code:

	function add(num1, num2) {
	return num1 + num2;

	}
	var res = add(7, 2);
	console.log(res);

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objectliteral8.js

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When you create a function as shown above, it is called a function declaration or statement. You can rewrite the code above to add a function in different ways, as shown below:

	var add = function (num1, num2) {
	return num1 + num2;
	}

	var res = add(7, 2);
	console.log(res);

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objectliteral10.js

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The function created above is called a function expression – in this case, an anonymous function expression. A named function expression can be created as below:

	var add = function a(num1, num2) {
	return num1 + num2;

	}
	var res = add(7, 2);
	console.log(res);

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objectliteral11.js

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The name of the function expression can only be used inside a function body, which is helpful in recursion. A function expression can either be a:

Named function expression
Anonymous function expression

The third method of creating a function is by using the Arrow function, which was introduced in ECMAScript 6. You can learn more about Arrow functions here.

Read full article on the Infragistics blog