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.
TypeError: "x" has no properties
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
What went wrong?
Examples
null and undefined have no properties
js
null.foo;
// TypeError: null has no properties
undefined.bar;
// TypeError: undefined has no properties
See also
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/No_properties