Handy little regex for password validation

Here’s a handy little regular expression that makes use of positive lookahead assertions to match a password that contains at least:

• one uppercase character to (?=.*[A-Z])
• one lowercase character to (?=.*[a-z])
• one number to (?=.*\d)

Where these assertions are met it then restricts the match to strings which are between 8 and 15 characters in length to .{8,15}

Here it is in full

/(?=.*[A-Z])(?=.*[a-z])(?=.*\d).{8,15}/