MobXs

MobX is a state management library for JavaScript and TypeScript that enables scalable, predictable state through transparent reactive programming. It provides tools to create observable data, derive computed values, and react to changes with minimal boilerplate.

Core concepts are observable data, actions, computed values, and reactions. Observables track read and write access so changes propagate automatically to dependent data. Actions designate blocks that mutate state. Computed values derive from observables and are cached and updated automatically. Reactions, including autorun, run side effects in response to data changes.

MobX was created by Michel Weststrate and first released in 2015. It is framework-agnostic and widely used with React via mobx-react or mobx-react-lite, but it can be used with any UI framework or vanilla JavaScript. The project is MIT-licensed and maintained with ongoing releases that include proxy-based observables and improved TypeScript support.

MobX emphasizes fine-grained reactivity and minimal boilerplate. Modern versions use proxies to wrap observable state, allowing direct mutations inside actions while preserving predictable change propagation. The system tracks only data observed by consumers, reducing unnecessary updates and enabling scalable designs without enforcing a single architecture.

Common patterns include defining a store with observable properties, using computed getters for derived data, and marking mutating methods as actions. MakeAutoObservable simplifies setup, and bindings render components that observe the store. The ecosystem also provides reactions for non-UI side effects.