This is a reference entry from MDN Web Docs. A full explanation with fixes has not been written yet.
TypeError: Cannot redefine property: "x" (V8-based)
TypeError: can't redefine non-configurable property "x" (Firefox)
TypeError: Attempting to change value of a readonly property. (Safari)
- Category
- TypeError
- Severity
- error
- Runtime
- both
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Source: MDN Web Docs. Data fetched 2026-09-25T01:48:37.273Z.