Check if a variable is a JavaScript object.

This is a short guide on how to check if a variable or value if an object using JavaScript. In order to do this, we can use the typeof operator, which returns the data type of a given value in a string format.

Take a look at the following JavaScript snippet:

//An example object.
var example = {param: true};

//Check to see if variable is an object using the
//typeof operator
if(typeof example === 'object' && example !== null){
    console.log('Variable is an object!');
} else{
    console.log('Variable is not an object!');
}

In the example above:

• We created a simple JavaScript object.
• We used the typeof operator to check if the variable was equal to “object” and not equal to null.
• Finally, we printed the result out into the console.

Why do you have to check for null?

You’re probably wondering why I specifically checked to see if the value was null. This is because JavaScript’s typeof operator sees null values as objects.

Take the following example:

//A variable that has been set to null.
var test = null;

//The typeof operator will return "object"
console.log(typeof test);

If you run the JavaScript snippet above, you will see that the typeof operator returns “object”, despite the fact that the variable in question contains a null value.

Array types.

You should also be aware that the Array type evaluates to “object”. To prevent this, you add an extra check for arrays. Here is a sample of a custom function that I created, which also checks to see if the value is an array:

function isObject(val){
    if(typeof val === 'object' && val !== null && !Array.isArray(val)){
        return true;
    }
    return false;
}

Hopefully, this guide proved to be useful!