Introduction to MobX

a simple state management solution.


State Management......sound familiar?

a functional programming approach

three core principles:

1. store acts as a single source of truth

2. state is read-only and can only be changed by emitting an action

3. changes to state are made by pure functions - reducers





an object-oriented approach

key concepts:

1. actions - primary means to modify the state. They take sources of change like user events to modify the observable state.

2. observable state - any value that can be mutated.

3. computed values - derived automatically when relevant data (observable values) are modified.

4. reactions - side effects that display changes to the UI or help with logging to the console.






redux state lifecycle, a quick look

Visualizing MobX: 'it's like a spreadsheet!' 


  • the key first step to using MobX is to set your state and mark it as observable
  • this is signifying that these are values that can change over time, and that the values derived from these values must update accordingly


  • computed values are automatically derived from the state -- if any value that affects them changes they change with it
  • everything is synchronous - they update immediately (think of the spreadsheet formula)

@ @ @ @ @ @ @

what's a function decorator, anyway?

ES6 syntax for calling higher-order functions

a function that extends the behavior of a wrapped function but does not explicitly modify it.

with decorators

without decorators

let's put it all together

the @observer


incredibly manual

  • to update state: explicitly dispatch actions and subscribe to the store. The manual definition of middleware and reducers gives you a lot of control.


  • application is predictable, testable and easy to reason about.


  • lot's of boilerplate, you have to write everything yourself.





incredibly magical

  • to update state: describe observable values that can be mutated and in turn mutate other values. Action dispatching and subscribing is automatic.


  • application is still predictable but perhaps more difficult to test/debug.


  • easier learning curve and significantly less code to write!



key differences

Copy of MobX

By Michael Corleone

Copy of MobX

Introduction to MobX: A Simple State Management Solution

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