Overrides AbstractString::padStart
public function padStart(int $length, string $padStr = ' ') : static { if ('' === $padStr || !preg_match('//u', $padStr)) { throw new InvalidArgumentException('Invalid UTF-8 string.'); } $pad = clone $this; $pad->string = $padStr; return $this->pad($length, $pad, \STR_PAD_LEFT); }