# E0180: stray comma in function parameter

A function parameter can be a variable name, an array destructuring, or an object destructuring. It is a syntax error for a parameter name to be in parentheses with a comma:

    let firsts = data.map([(x,)] => x);

To fix this error, remove the comma:

    let firsts = data.map([x] => x);

Introduced in quick-lint-js version 1.0.0.

Documentation for other errors