Function includes

src/patterns.ts:881–884

(
  substr: substr
)

 *   .with(P.string.includes('http'), () => 'value contains http')
 */
const includes = <input, const substr extends string>(
  substr: substr
): GuardExcludeP<input, string, never> =>
  when((value) => isString(value) && value.includes(substr));

/**
 * `P.string.regex(expr)` is a pattern, matching **strings** that `expr` regular expression.