How to Fix TypeError: Null is Not an Object in JavaScript

The JavaScript error TypeError: null is not an object occurs when a property is accessed or a method is called on a null value. This specific error message is shown only on Safari. Other browsers display a different message for this error.

Error message:

TypeError: null is not an object (evaluating 'x.y') - Safari
TypeError: Cannot read properties of null (reading 'x') - Chrome
TypeError: x is null - Firefox

Error Type:

TypeError

What Causes TypeError: Null is Not an Object

The TypeError: null is not an object occurs when a property is read (or set) or a method is called on a null value. An object was expected in code but was not provided. Since null is not an object in JavaScript, using a null value when an object is expected does not work. A proper object must be provided in such situations.

TypeError: Null is Not an Object Example

Here’s an example of a TypeError: null is not an object thrown when trying to read a property of a null value:

var a = null;
console.log(a.b);

In the above code, the variable a has a null value. When the property b is attempted to be read on it, a TypeError: null is not an object is thrown:

TypeError: null is not an object (evaluating 'a.b')

How to Fix TypeError: Null is Not an Object

When such an error occurs, it means that a null value was provided where an object was expected. It should be ensured that the variable causing the error does not have a null value and is a proper object.

To avoid coming across situations where properties of null variables may be accessed accidentally, an if check should be added before dealing with such variables:

if (myVar !== null) {
    ...
}

Updating the previous example to include an if check:

var a = null;
if (a !== null) {
    console.log(a.b);
}

Running the above code avoids the error since the property b is only accessed if a is not null.

Track, Analyze and Manage Errors With Rollbar

Managing errors and exceptions in your code is challenging. It can make deploying production code an unnerving experience. Being able to track, analyze, and manage errors in real-time can help you to proceed with more confidence. Rollbar automates error monitoring and triaging, making fixing Javascript errors easier than ever. Sign Up Today!