Regex testing a string with uppercase letters, lowercase letters, numbers, special symbols, with no whitespace

I’m trying to evaluate a js string with a regex function that will detect the above mentioned criterias except for the symbols part, as I only need to evaluate if dots or underscores are in the string. An example is this:

mfv.3djtSewe5jCrg19A_fkdrOe8LG2zL7cY1oK4lEN5m3z6jh9bvpUlnxfP4qdbAwhuUruN_uKRv6trcROqXm4P

and the regex I’m using is this:

/^(?!.*s+$)(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[_.]).+$/

I’m new to javascript let alone regex matching and I’m not entirely sure how to do this.