Regular Expression for 1-9 or 01-09 or 10-12

programming web dev
1

I have a regular expression (being used in JavaScript) which successfully passes 01-09 AND 10-12.

It is:
/0[1-9]|1[012]/.test( someOneOrTwoDigitNumber );

true if: 01,02,…09,10,11,12

However, I cannot figure out how to modify it to allow 1-9 if only a single digit is entered.

Does any one know how? Thanks.