USM

USM is a universal state modular library, supports Redux(4.x), MobX(6.x), Vuex(4.x) and Angular(2.0+).

Motivation

usm provides a generic state model that is class-first, which help us to be OOP at almost no cost and is compatible with the ecology of every state library.

When you don't want to learn the paradigm of any state library, usm can help you use any state library. When your project's business code is based on usm, the architecture will be more flexible.

Support

Installation

To install usm:

yarn add usm # npm install --save usm

And if you want to use Redux/MobX/Vuex, you just install usm-redux/usm-mobx/usm-vuex.

Usage

• Use @state to decorate a module state.

• Use @action to decorate a module method for state changes.

• Use createStore to create a store.

import { state, action, createStore } from 'usm';
// You can also use `usm-redux`, `usm-mobx`, or`usm-vuex`.

class Counter {
  @state
  count = { sum: 0 };

  @action
  increase() {
    this.count.sum += 1;
  }
}

const counter = new Counter();

const store = createStore({
  modules: [counter],
});

counter.increase();

const newState = Object.values(store.getState())[0] as Counter;
expect(newState.count).toEqual({ sum: 1 });

Examples

• React
• Vue

APIs

@state

Define a shared state for a module, and you can use @state for decoration. When use usm-redux, the state is not allowed to be undefined.

For example,

class Counter {
  @state
  number = 0;
}

@action

All operations that change state must be in a method decorated by @action.

For example,

class Counter {
  @state
  number = 0;

  @action
  increase() {
    this.number += 1;
  }
}

@computed/@computed()

It is used for computing derived data.

• When use usm or usm-redux, you should use @computed(depsCallback), The return value of the depsCallback is an array of dependent value collections that tells the module that its getter will recompute when there is a change in any of the values in the value collections:

For example,

class Counter {
  @state
  count = { sum: 0 };

  @state
  number = 0;

  @action
  increase() {
    this.number += 1;
  }

  @computed((that) => [that.count.sum, that.number])
  get sum() {
    return this.count.sum + this.number;
  }
}

• When use usm-mobx or usm-vuex, you just use @computed, Since it is an observable model, its dependency collection is automatic:

For example,

class Counter {
  @state
  count = { sum: 0 };

  @state
  number = 0;

  @action
  increase() {
    this.number += 1;
  }

- @computed((that) => [that.count.sum, that.number])
+ @computed
  get sum() {
    return this.count.sum + this.number;
  }
}

createStore()

Creates a usm store that holds the complete shared state.

Arguments

• options(object)
  • modules(array): an array with all modules instances
  • [strict] (boolean): enable strict mode
• [preloadedState] (any): preloaded state
• [plugins/middleware] (any[]): vuex's plugins or redux's middleware

For example,

class Counter {
  @state
  number = 0;

  @action
  increase() {
    this.number += 1;
  }
}

const counter = new Counter();

const store = createStore({
  modules: [counter],
});

subscribe()

You can use subscribe() to subscribe state changes in any class module.

For example,

class Counter {
  constructor() {
    subscribe(this, () => {
      //
    });
  }

  @state
  count = { sum: 0 };
}

watch()

You can use watch() to observe a specific state changes in any class module.

For example,

class Counter {
  constructor() {
    watch(
      this,
      () => this.count.sum,
      (newValue, oldValue) => {
        //
      }
    );
  }

  @state
  count = { sum: 0 };
}

You can pass the option { multiple: true }, which will support watching multiple values.

For example,

class Counter {
  constructor() {
    watch(
      this,
      () => [this.count0, this.count1],
      ([newCount0, newCount1], [oldCount0, oldCount0]) => {
        //
      },
      {
        multiple: true,
      }
    );
  }

  @state
  count0 = 0;

  @state
  count1 = 0;
}

watch option supports passing in isEqual function for custom equal.