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JS
JavaScript error

SyntaxError

The JavaScript exception "invalid named capture reference in regular expression" occurs when a regular expression pattern contains a named backreference that does not refer to a named capture group before it. The similar error message "invalid named reference in regular expression" is thrown when the sequence \k is encountered but is not followed by <.

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: Invalid regular expression: /\k<x>/u: Invalid named capture referenced (V8-based)
As listed by MDN Web Docs
SyntaxError: invalid named capture reference in regular expression (Firefox)
As listed by MDN Web Docs
SyntaxError: Invalid regular expression: invalid \k<> named backreference (Safari)
As listed by MDN Web Docs
SyntaxError: Invalid regular expression: /\k/u: Invalid named reference (V8-based)
As listed by MDN Web Docs
SyntaxError: invalid named reference in regular expression (Firefox)
As listed by MDN Web Docs
SyntaxError: Invalid regular expression: invalid escaped character for Unicode pattern (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.