PACKAGE · STATE MANAGEMENT

mobx

Simple, scalable state management.

WEEKLY DOWNLOADS 1.9M
STARS 28.2K
FORKS 1.8K
OPEN ISSUES 72
GZIP SIZE 19.1 kB
UNPACKED SIZE 4.4 MB
DEPENDENCIES 1
LAST UPDATED 8mo ago
DOWNLOAD TRENDS

mobx downloads — last 12 months

Download trends for mobx1 download series from Jun 2025 to May 2026. Use left and right arrow keys to inspect monthly values.04.2M8.3M12.5M16.7MJun 2025SepDecMarMay 2026
mobx
ABOUT MOBX

MobX simplifies state management by making state observable and automatically tracking changes. It addresses the complexity of synchronizing application state with the UI, particularly in dynamic web applications, by providing a reactive programming paradigm. This allows developers to focus on modeling their data without manually handling updates.

The core philosophy of MobX is to automate as much as possible. It aims to keep state management simple and scalable, making it accessible to a wide range of developers, especially those working with component-based UIs. MobX treats state as a given and provides a mechanism to react to its changes efficiently.

Key API patterns in MobX revolve around making state observable using `makeObservable` or `makeAutoObservable`, and then using computed values (`computed`) and reactions (`autorun`, `reaction`, `when`). These constructs enable automatic updates to the UI or other side effects whenever the relevant observable state changes, eliminating the need for explicit dispatching or manual event handling.

MobX integrates seamlessly with various JavaScript frameworks and libraries, most notably React, via its `mobx-react-lite` or `mobx-react` packages. It also works well with TypeScript, offering robust type safety. The reactive nature of MobX makes it a good fit for applications where data flows and changes frequently, ensuring the UI stays consistent with the underlying state.

With a packed size of 4.4 MB and a gzipped bundle size of just 19.1 kB, MobX offers a relatively lightweight solution for its capabilities. Version 6.16.0, released on 2026-06-03, indicates a mature project with a long history and ongoing development. The significant number of GitHub stars (28.2K) and weekly downloads (4.1M) underscores its popularity and stability in the ecosystem.

A potential caveat is the learning curve associated with understanding reactive programming principles and MobX's specific decorators or observable patterns. While powerful, ensuring optimal performance might require careful consideration of how computations and reactions are structured to avoid unnecessary re-renders or excessive computations, especially in complex scenarios with many observables.

WHEN TO USE
  • When building complex, interactive UIs where state changes frequently and needs to be reflected across multiple components.
  • When you want to minimize boilerplate code associated with state updates compared to more imperative approaches.
  • When integrating state management into existing React applications using hooks like `useObserver` or `observer` (from `mobx-react-lite`).
  • When creating computed values derived from observable state that should automatically update when their source state changes.
  • When implementing background tasks or side effects that need to react to specific state changes using `autorun` or `reaction`.
  • When working with TypeScript and desiring type-safe observable state management.
WHEN NOT TO USE
  • If your primary state consists of simple, independent values—React's built-in `useState` and `useReducer` might suffice.
  • If you prefer a strictly unidirectional data flow with explicit actions for every state mutation, consider alternative patterns.
  • When dealing with global state that changes very infrequently and has minimal cross-component impact, leading to potential over-engineering.
  • If the overhead of learning and applying the MobX reactive programming model is undesirable for a straightforward application.
  • When you need a state management solution that strictly enforces immutability patterns for all state updates.

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