function dupIgnoreCase()

in functions/param-names-unique.js [12:20]

• 7 lines of code
• 2 McCabe index (conditional complexity)

function dupIgnoreCase(arr) {
  if (!Array.isArray(arr)) {
    return [];
  }

  const isDup = (value, index, self) => self.indexOf(value) !== index;

  return [...new Set(arr.map((v) => canonical(v)).filter(isDup))];
}