What is a return value of a function in JavaScript?

When a return statement is used in a function body, the execution of the function is stopped. If specified, a given value is returned to the function caller. For example, the following function returns the square of its argument, x , where x is a number.

Do JavaScript functions have to return a value?

To return a value other than the default, a function must have a return statement that specifies the value to return. A function without a return statement will return a default value. In the case of a constructor called with the new keyword, the default value is the value of its this parameter.

What does empty return mean in JavaScript?

“Blank return” statements can be used to transfer the control back to the calling function (or stop executing a function for some reason – ex: validations etc). In most cases I use blank return statement is when I’m doing some kind of a validation.

Why does a function return undefined?

A function returns undefined if a value was not returned . Note: While you can use undefined as an identifier (variable name) in any scope other than the global scope (because undefined is not a reserved word), doing so is a very bad idea that will make your code difficult to maintain and debug.

Why is my function returning undefined JavaScript?

Do functions need to return a value?

Answer. NO, a function does not always have to have an explicit return statement. If the function doesn’t need to provide any results to the calling point, then the return is not needed.

What happens when a function returns nothing?

Void functions are created and used just like value-returning functions except they do not return a value after the function executes. In lieu of a data type, void functions use the keyword “void.” A void function performs a task, and then control returns back to the caller–but, it does not return a value.

What JavaScript method returns undefined?

If you never return a value from a function in JavaScript, you implicitly return undefined . Copied! This is the most common reason the map() method returns an array containing undefined values. A rare, but also possible problem might be that you explicitly return an undefined value from the function.

What is the difference between null and undefined?

Definition: Null: It is the intentional absence of the value. It is one of the primitive values of JavaScript. Undefined: It means the value does not exist in the compiler.