Javascript calculator test13 using mathjs

I have finished the calculator, but can’t pass test 13 (two consecutive operators). I’ve done it in a way where you can’t type 2 consecutive operators and that was the only test left. So I rewrote part of it to pass test 13, but I can’t figure it out.

I have tried using 2 separate strings (one for display and another for the calculations) and omitting the extra operators from the calculations string, but no dice.

Here’s my codepen:

I figured it out. I edited the expression before using mathJS and replaced the consecutive operators by the last one using RegExp.