Javascript Regex to match only a single occurrence no more or less

Question

I have a string like below:

single-hyphen

I need to match the hyphen. However, I only want to match a single occurrence of the hyphen, no more or less.

So the string above will return true, but the two below will be false:

1. a-double-hyphen
2. nohyphen

How do I define a regex to do this?

Thanks in advance.

Answer 1

You can do this

/^[^-]+-[^-]+$/

^ depicts the start of the string

$ depicts the end of the string

[^-]+ matches 1 to many characters except -

Answer 2

/^[^-]*-[^-]*$/

Beginning of string, any number of non-hyphens, a hyphen, any number of non-hyphens, end of string.