Type Safe State Machines in TypeScript

See the original posting on DZone Python

State machines are everywhere but I don’t think they get enough air time. To remedy the situation I’m going to present an implementation in TypeScript and use it to model a very simple elevator.

I could point you to the definition of what a state machine is on Wikipedia but the name gives it away. State machines consist of states and a description of how to go from one state to the next. So let’s start spelling things out.