public static function isInteger( $input ): bool {
    return self::is( $input ) && (string) (int) $input === (string) $input;
  }
public static function isInteger( $input ): bool {
    return self::is( $input ) && (string) (int) $input === (string) $input;
  }
public static function isInteger ( $ input ) : bool { return self :: is ( $ input ) && ( string ) ( int ) $ input === ( string ) $ input ; }
Check if the input is true integer number or can be converted from string into integer

@param mixed $input

@return bool
Check if the input is true integer number or can be converted from string into integer