This is the javascript regular expression I'm confused about. I know that (?=) is the positive lookahead, but is there suppose to have a main expression before that?
/^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])\w{8,}$/
The answer says it matches a password which is:
at least one number, one lowercase and one uppercase letter and at least 8 characters that are letters, numbers or the underscore
But I don't see why. Can somebody explain a little?