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JS
JavaScript error

SyntaxError

The JavaScript exception "super() is only valid in derived class constructors" occurs when the super() call is used somewhere that's not the body of a constructor in a class with extends keyword.

Reference entryJavaScriptFetched
This is a reference entry from MDN Web Docs. A full explanation with fixes has not been written yet.

The error messages

SyntaxError: 'super' keyword unexpected here (V8-based)
As listed by MDN Web Docs
SyntaxError: super() is only valid in derived class constructors (Firefox)
As listed by MDN Web Docs
SyntaxError: super is not valid in this context. (Safari)
As listed by MDN Web Docs

Details

Category
SyntaxError
Severity
error
Runtime
both

Related errors

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Source: MDN Web Docs. Data fetched 2026-09-25T01:48:37.273Z.