Blueprint

This document outlines the core behaviors of MobX that need to be implemented for an effective reactive system.

Core Actors

Atom

Observable<T>

• Can be observed and intercepted

Derivation

• Depends on a set of observables to do its work.

Computed<T>

• Is an observable which derives its value from a set of dependent observables
• Compare values structurally or as scalars

Reaction

• Reactions are scheduled with a sync-scheduler or debounced with a timer-based scheduler
• They are derivations with no output value and only cause side-effects
• Handle exceptions and report them back with global handlers
• Can dispose
• Checks for convergence with 100 iterations

Global Tracker

• Used to push pending reactions
• Determine the underlying dependencies when derivations are executed
• Keeps track of current derivation
• Keeps track of the nesting depth and use that to execute affected reactions
• Works in a transactional manner for executing pending reactions

Action

• Provides an atomic way to mutate observables
• Fires notifications only upon the completion of the action
• Handles any level of nesting and ensures notifications are fired only when the outermost action has completed

API

• Convenience layer to provide programmer friendly interface to the Core Actors and behaviors

Cross cutting layers

• Memoization of computation with DependencyState
• Spying and Traceability
• Exception handling and propagation

Implementation Details

• Avoid dart:mirrors as it is not supported in Flutter