regex - Regular expression to match strings composed of ABAs or ABs -

i want write regular expression match strings composed of abas or of abs. here's regular expression right now:

(aba)+|(ab)+

i want match:

ab aba abab abaaba ababab 

but present regular expression not match abab.

if change (ab)+|(aba)+ not match aba.

how can write regular expression want?

what want regular expression matching "the longest substring matching (ab)+ or (aba)+".

you can try either /(aba?)+/gm - should give need.