#state-machine code explainers

javascript

const transitions = {
  cart: { checkout: 'shipping' },
  shipping: { submitAddress: 'payment', back: 'cart' },
  payment: { submitPayment: 'review', back: 'shipping' },

A finite state machine for checkout flow

state-machine event-driven data-driven-design

Intermediate 7 steps

typescript

type CheckoutState = "cart" | "shipping" | "payment" | "review" | "confirmed";
 
type CheckoutEvent =
  | { type: "PROCEED" }

A typed checkout state machine in TypeScript

state-machine union-types type-safety

Intermediate 7 steps

rust

/// A custom iterator that yields Fibonacci numbers up to a maximum value.
pub struct Fibonacci {
    current: u64,
    next: u64,

Building a custom Fibonacci iterator in Rust

iterators traits state-machine

Intermediate 6 steps

javascript

const PENDING = 'pending';
const FULFILLED = 'fulfilled';
const REJECTED = 'rejected';

Building a Promise from scratch

promises state-machine microtasks

Advanced 10 steps