How do you return a null from a function?

7 Answers. If you don’t return anything, just use return; or omit it at all at the end of the function. If your function is usually returns something but doesn’t for some reason, return null; is the way to go.

Should 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.

What does return null return?

A function that returns a null reference achieves neither goal. Returning null is like throwing a time bomb into the software. Other code must a guard against null with if and else statements.

What is return () in JavaScript?

The return statement ends function execution and specifies a value to be returned to the function caller.

Is returning NULL bad practice?

Returning Null is Bad Practice The FirstOrDefault method silently returns null if no order is found in the database. Getting a null value is an ambiguous for caller, because it doesn’t say whether the null is returned due to the bug or due to the fact that the order was not found in the database.

Is it good to return null in Java?

Returning a possibly- null object from a method is usually undesirable. The caller of such a method may not be aware that it can return null . If the caller has not written code to handle the null case, and a null is returned, then an error will almost always result.

Is it better to use null or undefined JavaScript?

Only use null if you explicitly want to denote the value of a variable as having “no value”. As @com2gz states: null is used to define something programmatically empty. undefined is meant to say that the reference is not existing. A null value has a defined reference to “nothing”.

Is it better to return NULL or empty string?

Returning null is usually the best idea if you intend to indicate that no data is available. An empty object implies data has been returned, whereas returning null clearly indicates that nothing has been returned.

Why return NULL is bad?

This is a violation of DRY principle. Getting a null value is an ambiguous for caller, because it doesn’t say whether the null is returned due to the bug or due to the fact that the order was not found in the database. Returning null is definitely not a domain-driven design approach.

Does return end a function JavaScript?

The return statement stops the execution of a function and returns a value from that function.

Do JavaScript functions have to return a value?

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.

Why is null a bad idea?

NULL exacerbates poor language decisions Java silently converts between reference and primitive types. Add in null, and things get even weirder. though it throws a NullPointerException when run. It’s bad enough that member methods can be called on null; it’s even worse when you never even see the method being called.

Why is there a `null` value in JavaScript?

T he JavaScript primitive type null represents an intentional absence of a value – it is usually set on purpose to indicate that a variable has been declared but not yet assigned any value. This contrasts null from the similar primitive value undefined , which is an unintentional absence of any object value.

What does mean by null in JavaScript?

NULL in Javascript A variable is a storage location that contains a value. A null represents nothing. Its not an actual value.

How to check undefined in JavaScript?

To check undefined in JavaScript, use (===) triple equals operator. In modern browsers, you can compare the variable directly to undefined using the triple equals operator. There are also two more ways to check if the variable is undefined or not in JavaScript, but those ways are not recommended.

What is a null value in JavaScript?

null and undefined are primitive values in JavaScript.