JS Tip of the Day: typeof null === "object"

typeof null === "object"
Level: Beginner

The typeof operator is used to identify the basic type of a value in JavaScript. It can individually identify primitive types as well as recognize any other object type as being an object (with a special case for recognizing function objects as functions).

console.log(typeof 1); // number
console.log(typeof "text"); // string
console.log(typeof undefined); // undefined
console.log(typeof {}); // object
console.log(typeof function () {}); // function
// ...

One particular quirk with typeof is that it will report the type of the value null as “object”.

console.log(typeof null); // object

Because of this, if you’re using typeof to check for objects in your code, you may also want to include a check to make sure it is not also null. Otherwise, you might be accidentally using a null value as an object in a way that could cause errors.

if (typeof someValue === "object" && someValue !== null) {
    // I don't object to the use of this object

More info: