Mobx State Tree

Posted September 4, 2023 by Rohith and Anusha ‐ 2 min read

State management is a crucial aspect of building modern web applications. Handling complex state logic can quickly become overwhelming, especially when dealing with larger codebases. Fortunately, there's a powerful TypeScript-friendly library that can help: Mobx-State-Tree (MST).

What is Mobx-State-Tree (MST)?

  • Mobx-State-Tree is a state management library inspired by Mobx and Redux, designed to bring predictability, simplicity, and ease of use to your state management code.

  • MST leverages TypeScript to provide a strongly typed and structured approach to managing application state.

  • It offers features like computed values, actions, and reactions to make state management a breeze.

Key Features of Mobx-State-Tree

Before delving into TypeScript integration, let’s highlight some of MST’s key features:

Hierarchical State

  • MST encourages you to structure your state as a hierarchical tree, making it easy to organize and manage even complex state structures.

Observable State

  • MST makes your state observable, automatically tracking changes and efficiently updating components that depend on it.


  • You can define actions to modify state in a controlled and predictable way.

  • TypeScript ensures that actions adhere to the specified type constraints.

Computed Values

  • MST allows you to derive computed values from your state, eliminating the need for redundant data storage.

Type Safety

  • TypeScript provides strong type-checking for your MST models, ensuring that your state is used correctly throughout your application.

TypeScript Integration

Here’s how TypeScript enhances your experience when using Mobx-State-Tree:

Strong Typing

  • TypeScript ensures that your state models, actions, and computed values have correct types, reducing runtime errors and improving code quality.
import { types, flow } from "mobx-state-tree";

const Todo = types
  .model("Todo", {
    id: types.identifierNumber,
    title: types.string,
    completed: false,
  .actions((self) => ({
    toggle() {
      self.completed = !self.completed; // TypeScript enforces correct typing here.

const todoStore = types
  .model("TodoStore", {
    todos: types.array(Todo),
  .actions((self) => ({
    addTodo(title: string) {
      self.todos.push({ id:, title });

const store = todoStore.create({ todos: [] });

Editor Autocompletion

  • TypeScript provides excellent editor autocompletion support, helping you discover available actions and model properties as you write code.

Type-Checked Actions

  • When you define actions, TypeScript ensures that they adhere to the correct type signatures, preventing accidental misuse.

Safe Model Composition

  • When building complex models by composing smaller models, TypeScript helps ensure that you maintain proper type safety throughout your state tree.


  • Mobx-State-Tree, when combined with TypeScript, offers a robust and maintainable solution for state management in your web applications.

  • It promotes a structured approach to state management, reduces runtime errors, and enhances your development experience with strong typing and autocompletion.

  • If you’re building a TypeScript-based application and looking for an efficient state management solution, consider integrating Mobx-State-Tree into your project.

  • It will help you manage complex state logic with ease and confidence.

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