javascript - Rewrite Regex to to be used in comparing? -

how can rewrite regex?

var exp = /(070|071|072|073|074|075|076|077|078|079)\d{7,8}$/; 

can this;

var exp[] = {070,071,072,073,074,075,076,077,078,079}; 

the simplest change use:

var exp = /(07\d)\d{7,8}$/; 

instead of listing out each of ten consecutive digits.