Javascript test ( object && object !== “null” && object !== “undefined” )

Question

I seem to be using this test a lot

if( object && object !== \"null\" && object !== \"undefined\" ){
    doSomething();
}

on

Answer 1

This should work without any issue.

if(object){ // checks for null and undefined
    doSomething();
}

Answer 2

I don't think you can make that any simpler, but you could certainly refactor that logic into a function:

function isRealValue(obj)
{
 return obj && obj !== 'null' && obj !== 'undefined';
}

Then, at least your code becomes:

if (isRealValue(yourObject))
{
 doSomething();
}

Answer 3

I think you could simplify a bit your logic with the following:

if (object != null && typeof(object) == "object") {
    doSomething();
}

The main problem is that if you just check typeof(object) == "object", it will return true if object is null since null's type is "object". However, if you first check that object != null, you can be sure you are having something that is neither undefined nor null.

Answer 4

If object is truthy, we already know that it is not null or undefined (assuming that the string values are a mistake). I assume that a not null and not undefined test is wanted.

If so, a simple comparison to null or undefined is to compare != null.

if( object != null ){
    doSomething();
}

The doSomething function will run only if object is neither null nor undefined.

Answer 5

maybe like this

   if (typeof object !== "undefined" || object !== null)
    // do something

Answer 6

The best way to check if an object is empty is by using a utility function like the one below.

create a function

function isEmpty(obj) {
    for(var key in obj) {
        if(obj.hasOwnProperty(key))
            return false;
    }
    return true;
}

Use above function following way:-

So if you have an empty object, you can check whether it is empty by using the above function.

var myObj = {}; // Empty Object
if(isEmpty(myObj)) {
    // Object is empty (Would return true in this example)
} else {
    // Object is NOT empty
}