isRegex

Problem

You need to check whether a value is a RegExp instance — for example validating a config option that accepts either a string pattern or a compiled regex.

Solution

Use isRegex(value) to narrow to RegExp.

import { isRegex } from '@vielzeug/arsenal';

function toRegex(pattern: string | RegExp): RegExp {
  return isRegex(pattern) ? pattern : new RegExp(pattern);
}

Related

• isString