Prototypes of a modern calculator could be coded in Java-Script or Dart and presented
on a browser.
I seriously question whether JavaScript's internal number representation would be accurate enough to implement a calculator for use in education. All numbers in JavaScript are represented as double-precision floats, which IMHO are not going to be accurate enough for engineering or science use (except, perhaps, with some very fancy footwork on the part of the developer).
Also, my understanding is that phones, tablets and the like are not allowed in classrooms precisely because their broad programmability makes it easy for students to cheat. How hard would it be for a student to flip back and forth between an app that looks like a calculator and a browser window with all the answers in it? Hardware calculators offer educators some assurance that this isn't happening.