Welcome to my calculator project !
I did as requested, a calculator on the WEB that is capable of doing a series of arithmetic operations, and showing the history.
About the history i saved it in the local storage to have a different history per user (i would have usually used a service as Auth0 and save the history in the DB).
The only issue that i had was to find a solution for the order of operations in a serie of operations.
I had the idea of a tree with a recursive, I checked online and found the Suffix (or Postfix) expressions.
I compared both solutions and found out that the second one is the best so i went to this idea.
I used a queue and temporary stack to build and solve it, and wrote unit tests for each step.
I separated everything on the Web and API for it to be re-usable, easy to maintain and change.
Handled errors and showed in case of situations like dividing by 0..
To make it work just rebuild the solution of the backend and to npm i on the web.
I'm available if you have questions.
Thank you and have a nice day.