Understanding React and reimplementing it from scratch Part 1: Views

I started a journey to understand what can be generalized and unified in the different implementations of a React-like library. The best way I know to understand something isn't just to learn how it works but which problems it's trying to solve and why it's designed that way. I'll start with a bare model and then I'll add feature after feature trying to explain the design decisions, pointing when possible to the corresponding implementations in React, Mitrhil and Mercury. What follows is my own interpretation of React, feel free to criticize and contribute.