What does a function return if it has no return statement in it?
If no return statement appears in a function definition, control automatically returns to the calling function after the last statement of the called function is executed. In this case, the return value of the called function is undefined.
“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).
So to recap: No, a JS function needn’t return anything as far as your code goes. But as far as the JS engines are concerned: a function always returns something, be it explicitly via a return statement, or implicitly. If a function returns implicitly, its return value will always be undefined.
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.
Does a function have to return a value?
If a function is defined as having a return type of void , it should not return a value. … If a function is defined as having a return type other than void , it should return a value.
What does a void function return?
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. You may or may not use the return statement, as there is no return value.
Can a function return a struct?
You can return a structure from a function (or use the = operator) without any problems. It’s a well-defined part of the language. The only problem with struct b = a is that you didn’t provide a complete type.
Can a void method have a return statement?
Any method declared void doesn’t return a value. It does not need to contain a return statement, but it may do so. … The data type of the return value must match the method’s declared return type; you can’t return an integer value from a method declared to return a boolean.
Should I return null or undefined?
Undefined typically refers to something which has not yet been assigned a value (yet). Null refers to something which definitively has no value. In that case, I would recommend returning a null. Note that a function with no specified return value implicitly returns undefined.
4 Answers. void(): This operator allows inserting expressions that produce side effects into places where an expression that evaluates to undefined is desired. The void operator is often used merely to obtain the undefined primitive value, usually using “void(0)” (which is equivalent to “void 0”).
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.
Calling the function with () in a return statement executes the function, and returns whatever value was returned by the function. It is similar to calling var x = b(); , but instead of assigning the return value of b() you are returning it from the calling function a() .
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.