What does return in JavaScript do?

What is the use of return 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. If the value is omitted, undefined is returned instead.

What does return true do in Javascript?

Rule #1. Every function in JavaScript returns undefined unless otherwise specified. As expected, when we invoke our function undefined is returned in the console. As you can see, our explicitly returned true value replaces the default undefined value.

Do Javascript functions need return?

No; Javascript functions are not required to return a value. If you call a function that doesn’t return a value, you’ll get undefined as the return value.

What does the return function do?

A return statement ends the execution of a function, and returns control to the calling function. Execution resumes in the calling function at the point immediately following the call. A return statement can return a value to the calling function.

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What is the difference between return and console log?

return is a statement that allows a function to output a value back to where it was called. console. log is a function that lets us inspect values for debugging purposes.

How does a function return a value?

To return a value from a function, you must include a return statement, followed by the value to be returned, before the function’s end statement. If you do not include a return statement or if you do not specify a value after the keyword return, the value returned by the function is unpredictable.

Is return the same as return true?

No. They are not the same. Returning false from a function returns the boolean false , where a void return will return undefined .

Why we use return false?

You use return false to prevent something from happening. So if you have a script running on submit then return false will prevent the submit from working. When a return statement is called in a function, the execution of this function is stopped. If specified, a given value is returned to the function caller.

Is NaN function JavaScript?

JavaScript isNaN() Function

The isNaN() function determines whether a value is an illegal number (Not-a-Number). This function returns true if the value equates to NaN. Otherwise it returns false. This function is different from the Number specific Number.

Do you always have to return something from a function?

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.

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What will be returned if f AB is called?

If a and b both are equal, then this function will return 0. In other case function f(a,b) will return positive integer and upon calling function g it will always return 1.

Should a function contain a return statement if it does not return a value?

A value-returning function should include a return statement, containing an expression. If an expression is not given on a return statement in a function declared with a non- void return type, the compiler issues a warning message. … For a function of return type void , a return statement is not strictly necessary.