Writing about XState

In order to add some behaviors to a state machine, we can change it, or we can add another machine in front of it to delegate some responsibilities. In this article I present the machine we added in front of our main machine to manage the load button of our Turing machine visualizer.

The are few things as boring as not knowing the state of an application. Is this document saved or should I Ctrl+S? In this article I present the stale data indicator we display on our Turing machine visualizer when visualizer is not in sync with inputs.

Loading indicators tell users that something is happening and will complete soon. They exist to improve UX, but they can worsen UX if they are directly hidden after underlying HTTP requests resolve. In this article I share XState patterns I used to prevent this issue in our Turing machine visualizer.

We built a Turing machine visualizer but it does not execute machines itself—it's the job of an Erlang server. The visualizer needs to make a request to execute machines, and XState is the perfect tool to orchestrate this in combination with other behaviors of the visualizer.

The execution of a Turing machine with an input produces a list of operations on a tape, that are made to be visualized. I built such a visualizer with XState, and used cool patterns to visualize operations on the tape.

Deciding where to put logic code in React applications is crucial to keep a codebase clean and maintainable, and even functional. Rethinking the place of the logic to go from top to bottom can help a lot, and it's the main purpose of XState.

Testing Library brings a formidable waitFor function to your tests to wait for a condition to be met before a timeout is reached. But sometimes we need such a function outside of client-side tests.

SCXML is an universal format to describe state machines. XState can be used to interpret them in JavaScript.

All transitions are external by default with XState, except transitions with a relative target, that are internal. It can lead to bugs when not understood properly.

Parallel states are an advanced feature of statecharts that allows to run a set of child states concurrently. We can even synchronize them easily by using normal XState events.