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JS
JavaScript error

SyntaxError

The JavaScript exception "setter functions must have one argument" occurs when a setter is declared and the parameter list is not consisted of exactly one formal parameter.

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: Setter must have exactly one formal parameter. (V8-based)
As listed by MDN Web Docs
SyntaxError: Setter function argument must not be a rest parameter (V8-based)
As listed by MDN Web Docs
SyntaxError: setter functions must have one argument (Firefox)
As listed by MDN Web Docs
SyntaxError: Unexpected token ','. setter functions must have one parameter. (Safari)
As listed by MDN Web Docs
SyntaxError: Unexpected token '...'. Expected a parameter pattern or a ')' in parameter list. (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 2026-09-25T01:48:37.274Z.