TypeError: "x" has no properties

The JavaScript exception "null (or undefined) has no properties" occurs when you attempt to access properties of null and undefined. They don't have any.

Message

TypeError: Cannot read properties of undefined (reading 'x') (V8-based)
TypeError: null has no properties (Firefox)
TypeError: undefined has no properties (Firefox)
TypeError: undefined is not an object (evaluating 'undefined.x') (Safari)

Error type

TypeError.

What went wrong?

Both null and undefined, have no properties you could access.

Examples

null and undefined have no properties

js

null.foo;
// TypeError: null has no properties

undefined.bar;
// TypeError: undefined has no properties

See also