JavaScript TypeError – “X” is not a non-null object
This JavaScript exception is not a non-null object that occurs if an object is not passed where it is expected. So the null is passed which is not an object and it will not work.
Message:
TypeError: Invalid descriptor for property {x} (Edge)
TypeError: "x" is not a non-null object (Firefox)
TypeError: Property description must be an object: "x" (Chrome)
TypeError: Invalid value used in weak set (Chrome)
Error Type:
TypeError
Cause of Error: Somewhere in the code an object is expected and is not passed. Automatically null is passed which is not an object and it will not work. User needs to provide a proper object in the given context.
Example 1: In this example, 1 is passed in the given method which is a non-null object, So the error has occurred.
HTML
<!DOCTYPE html><html><head> <title>Type Error</title></head><body> <script> // 1 is non-null object Object.defineProperty({}, 'prop_name', 1); </script></body></html> |
Output(In Chrome console):
TypeError: Property description must be an object: 1
Example 2: In this example, the WeakSet object store object keys, Other types of keys are not accepted. So the error has occurred.
HTML
<!DOCTYPE html><html><head> <title>Type Error</title></head><body> <script> var var1 = new WeakSet(); var1.add('GFG'); </script></body></html> |
Output(In Chrome console):
TypeError: Invalid value used in weak set
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