Purpose

This library is inspired by Vue.js implementation of reactivity. You can familiarize with the concept of reactivity here. Short excerpt:

Reactivity is a programming paradigm that allows us to adjust to changes in a declarative manner.

However Vue.js reactivity is limited to synchronous computation. This library solves this limitation and supports both - synchronous and asynchronous computation.

You can familiarize with sample use here.

Concepts

We refer to values of many variables as "state".

We refer to values of many reactive variables as "reactive state".

For reactive state to be reactive dependencies need to be tracked. So it is easier to think about reactive state as a dependency graph (for example A → B → C). Here A → B means:

• A depends on B
• B is dependency
• A is dependent

There are few types of reactive variables:

• ref
  • simply stores a given value (Vue.js shallowRef equivalent)
  • can only be dependency (only incoming arrows)
• computed
  • defined by pure function (Vue.js computed equivalent)
  • can be both - dependent and dependency (incoming and outgoing arrows)

To integrate state with reactive state you can use:

• listener
  • inherits ref
    • can only be dependency (only incoming arrows)
  • start function is called when listener gets first dependent
    • it ensures value is updated
  • stop function is called when listener loses last dependent
• watcher
  • a function that is called when dependency changes
  • can only be dependent (only outgoing arrows)

Behavior

You can familiarize with behavior by reading tests.