illustration for Introduction to State Machines Using XState

Introduction to State Machines Using XState


Kyle Shevlin
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The difficulty of managing state is one of the primary reasons our applications become so complex. We try and manage this complexity with a lot of booleans, somewhat semantic variables like isLoading, wasFetched, and hasError, and over-engineered systems that are still full of bugs. Surely, there's a better way.

That better way is state machines.

State machines formalize how we define and transition through the states of our application and give us ultimate control of the most complex parts of our apps.

In this course, we will explore the problems state machines purport to solve, like boolean explosion. We'll try to solve it our own way first, get so far, and then demonstrate how state machines get us all the way. After that, we'll dive into the XState library, JavaScript's premiere state machine library, to learn its API and how to use it to solve our problems.

By the time you're done taking this course, you should have a solid education about state machines and be able to start applying them.


Maxime Bourgeois (illustration)

What you'll learn

  • Build a simple machine for a piece of UI
  • Build Hierarchical, Parallel, and, History state machines
  • Identify the conditions & implement transition guards
  • Trigger Actions on transition
  • Handle infinite states when working with inputs
  • Understand Activities