javascript - Regex to match '-' delimited alphanumeric words

Question

I would like to test if user type only alphanumeric value or one "-".

hello-world                 -> Match
hello-first-world           -> match
this-is-my-super-world      -> match
hello--world                -> NO MATCH
hello-world-------this-is   -> NO MATCH
-hello-world                -> NO MATCH (leading dash)
hello-world-                -> NO MATCH (trailing dash)

Here is what I have so far, but I dont know how to implement the "-" sign to test it if it is only once without repeating.

var regExp = /^[A-Za-z0-9-]+$/;

Answer 1

Try this:

/^[A-Za-z0-9]+(?:-[A-Za-z0-9]+)*$/

This will only match sequences of one or more sequences of alphanumeric characters separated by a single -. If you do not want to allow single words (e.g. just hello), replace the * multiplier with + to allow only one or more repetitions of the last group.