1. mobx #

mobx是一个简单可扩展的状态管理库

2. mobx vs redux #

mobx学习成本更低，性能更好的的状态解决方案

3. 核心思想 #

状态变化引起的副作用应该被自动触发

flow

4. 环境准备 #

4.1 安装依赖模块 # 

pm i webpack webpack-cli babel-core babel-loader babel-preset-env babel-preset-react babel-preset-stage-0 babel-plugin-transform-decorators-legacy mobx mobx-react -D

4.2 webpack.config.js # 

const path=require('path');
module.exports = {
    mode: 'development',
    entry: path.resolve(__dirname,'src/index.js'),
    output: {
        path: path.resolve(__dirname,'dist'),
        filename:'main.js'
    },
    module: {
        rules: [
            {
                test: /\.jsx?$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['env','react','stage-0'],
                        plugins:['transform-decorators-legacy']
                    }
                }
            }
        ]
    },
    devtool:'inline-source-map'
}

4.3 package.json # 

"scripts": {
    "start": "webpack -w"
},

5. Decorator #

5.1 类的修饰 # 

@testable
class Person{

}
//修改了Person的类的行为，增加了静态属性isTestable
function testable(target) {
    target.isTestable=true;
}
console.log(Person.isTestable)

@decorator
class A{}
---------------
class A{}
A = decorator(A);

5.2 修饰属性 # 

class Circle{
    @readonly PI=3.14;
}

//descriptor {value:func,enumerable:false,configurable:true,writable:true}
function readonly(target,name,descriptor) {
    console.log(descriptor);
    descriptor.writable=false;
}
let c1=new Circle();
c1.PI=3.15;
console.log(c1.PI);

5.3 修饰方法 # 

class Calculator{
    //@logger
    add(a,b) {
        return a+b; 
    }
}

function logger(target,name,descriptor) {
    let oldValue=descriptor.value;
    descriptor.value=function () {
        console.log(`${name}(${Array.prototype.join.call(arguments,',')})`);
        return oldValue.apply(this,arguments);
    }
}
let oldDescriptor=Object.getOwnPropertyDescriptor(Calculator.prototype,'add');
logger(Calculator.prototype,'add',oldDescriptor);
Object.defineProperty(Calculator.prototype,'add',oldDescriptor);

let calculator=new Calculator();
let ret = calculator.add(1,2);
console.log(ret);

6. Proxy # 

var proxy = new Proxy(target, handler);

let p1=new Proxy({name:'zfpx'},{
    get: function (target,key,receiver) {
        console.log(`getting ${key}`);
        console.log(receiver);
        return Reflect.get(target,key,receiver);
    },
    set: function (target,key,value,receiver) {
        console.log(`setting ${key}`);
        return Reflect.set(target,key,value,receiver);
    }
});
console.log(p1.name);

7. mobx #

7.1 observable #

7.1.1 引用类型 (observable) #

类型 描述
对象
数组 
const {observable,isArrayLike}=require('mobx');
function observable2(target) {
    return new Proxy(target,{});
}
const p1=observable2({name:'zfpx'});
console.log(p1.name);

const {observable}=require('mobx');
function observable2(target) {
    return new Proxy(target,{

    });
}
const p1=observable([1,2,3]);
p1.push(4);
p1.pop();
console.log(p1);
console.log(Array.isArray(p1));

7.1.2 基本类型(observable.box) #

类型 描述
String 字符串
Boolean 布尔值
Number 数字
Symbol 独一无二的值 
const {observable}=require('mobx');
let num=observable.box(10);
let str=observable.box('hello');
let bool=observable.box(true);
console.log(num.get(),str.get(),bool.get());
num.set(100);
str.set('world');
bool.set(false);
console.log(num.get(),str.get(),bool.get());

7.1.3 decorator # 

import {observable} from 'mobx';
class Store {
    @observable name='zfpx';
    @observable age=9;
    @observable isMarried=false;

    @observable hobbies=[];
    @observable home={name:'北京'};
    @observable skills=new Map();
}

8. 使用对可观察对象做出响应 #

8.1 computed # 


let {observable,computed} = require('mobx');
class Store {
    @observable name='zfpx';
    @observable age=9;
    @observable area='010';
    @observable number="18910092296"

    @observable province="广东";
    @observable city="东莞";
    @computed get home() {
        return this.province+this.city;
    }
}

let store=new Store();
let cell = computed(function () {
    return store.area+'-'+store.number;
});
cell.observe(change=>console.log(change));
console.log(cell.get());
store.area='020';
store.number='15718856132';
console.log(cell.get());
console.log(store.home);
store.province='山东';
store.city='济南';
console.log(store.home);

8.2 autorun # 

autorun(() => {
    //console.log(store.province,store.city);
    console.log(store.home);
});

store.province='山东';
store.city='济南';

8.3 when # 

when(predicate: () => boolean, effect?: () => void, options?)

let dispose = when(() => store.age>=18,()=>{
    console.log('你已经成年了!')
});
dispose();
store.age=10;
store.age=20;
store.age=30;

8.4 reaction # 

reaction(() => [store.province,store.city],arr => console.log(arr.join(',')));
store.province='山东';
store.city='济南';

9. action # 

let {observable,computed,autorun,when,reaction,action} = require('mobx');
class Store {
    @observable province="广东";
    @observable city="东莞";
    @action moveHome(province,city) {
         this.province=province;
         this.city=city;
    }
}
let store=new Store();
reaction(() => [store.province,store.city],arr => console.log(arr.join(',')));
store.moveHome('山东','济南');

9.2 action.bound # 

let {observable,computed,autorun,when,reaction,action} = require('mobx');
class Store {
    @observable province="广东";
    @observable city="东莞";
    @action.bound moveHome(province,city) {
         this.province=province;
         this.city=city;
    }
}
let store=new Store();
reaction(() => [store.province,store.city],arr => console.log(arr.join(',')));
let moveHome=store.moveHome;
moveHome('山东','济南');

9.3 runInAction # 

runInAction(() => {
    store.province='山东';
    store.city='济南';
});

10. mobx应用 #

10.1 计数器 # 

import React,{Component} from 'react';
import ReactDOM from 'react-dom';
import {observable,action} from 'mobx';
import PropTypes from 'prop-types';
import {observer} from 'mobx-react';

class Store {
    @observable number=0;
    @action.bound add() {
        this.number++;
    }
}
let store=new Store();

@observer
class Counter extends Component{
    render() {
        return (
            <div>
                <p>{store.number}</p>
                <button onClick={store.add}>+</button>
            </div>
        )
    }
}
ReactDOM.render(<Counter/>,document.querySelector('#root'));

import React,{Component} from 'react';
import ReactDOM from 'react-dom';
import {observable,action} from 'mobx';
import PropTypes from 'prop-types';
import {observer} from 'mobx-react';

class Store {
    @observable counter={number:0};
    @action.bound add() {
        this.counter.number++;
    }
}
let store=new Store();
@observer
class Counter extends Component{
    render() {
        return (
            <div>
                <p>{this.props.counter.number}</p>
                <button onClick={this.props.add}>+</button>
            </div>
        )
    }
}
ReactDOM.render(<Counter
    counter={store.counter}
    add={store.add}
/>,document.querySelector('#root'));

10.2 TODO # 

import React,{Component,Fragment} from 'react';
import ReactDOM from 'react-dom';
import {observable,action, computed} from 'mobx';
import PropTypes from 'prop-types';
import {observer,PropTypes as ObservablePropTypes} from 'mobx-react';
class Todo{
    id=Math.random();
    @observable text='';
    @observable completed=false;
    constructor(text) {
        this.text=text;
    }
    @action.bound toggle() {
        this.completed=!this.completed;
    }
}
class Store{
    @observable todos=[];
    @computed get left() {
        return this.todos.filter(todo=>!todo.completed).length;
    }
    @computed get filterTodos() {
        return this.todos.filter(todo => {
            switch (this.filter) {
                case 'completed':
                    return todo.completed;
                case 'uncompleted':
                    return !todo.completed;
                default:
                    return true;
            }
        });
    }
    @observable filter='all';
    @action.bound changeFilter(filter) {

        this.filter=filter;
        console.log(this.filter);
    }
    @action.bound addTodo(text) {
        this.todos.push(new Todo(text));
    }
    @action.bound removeTodo(todo) {
        this.todos.remove(todo);
    }
}
@observer
class TodoItem extends Component{
    static porpTypes={
        todo: PropTypes.shape({
            id: PropTypes.number.isRequired,
            text: PropTypes.string.isRequired,
            completed:PropTypes.bool.isRequired
        }).isRequired
    }
    render() {
        let {todo}=this.props;
        return (
            <Fragment>
                <input
                    type="checkbox"
                    onChange={todo.toggle}
                    checked={todo.completed} />
                <span className={todo.completed? 'completed':''}>{todo.text}</span>

            </Fragment>
        )
    }
}
@observer
class TodoList extends Component{
    static propsTypes={
        store: PropTypes.shape({
            addTodo:PropTypes.func,
            todos:ObservablePropTypes.observableArrayOf(ObservablePropTypes.observableObject)
        }).isRequired
    };
    state={text:''}
    handleSubmit=(event) => {
        event.preventDefault();
        this.props.store.addTodo(this.state.text);
        this.setState({text:''});
    }
    handleChange=(event) => {
        this.setState({text:event.target.value});
    }
    render() {
        let {filterTodos,left,removeTodo,filter,changeFilter}=this.props.store;
        return (
            <div className="todo-list">
                <form onSubmit={this.handleSubmit}>
                    <input placeholder="请输入待办事项" type="text" value={this.state.text} onChange={this.handleChange}/>
                </form>
                <ul>
                    {
                        filterTodos.map(todo => (
                            <li key={todo.id}>
                                <TodoItem todo={todo} />
                                <button onClick={()=>removeTodo(todo)}>X</button>
                            </li>
                        ))
                    }
                </ul>
                <p>
                    <span>你还有{left}件待办事项!</span>
                    <button
                        onClick={()=>changeFilter('all')}
                        className={filter==='all'?'active':''}>全部</button>
                    <button onClick={() => changeFilter('uncompleted')}
                        className={filter==='uncompleted'?'active':''}>未完成</button>
                    <button
                        onClick={()=>changeFilter('completed')}
                        className={filter==='completed'?'active':''}>已完成</button>
                </p>
            </div>
        )
    }
}
let store=new Store();
ReactDOM.render(<TodoList store={store}/>,document.querySelector('#root'));

11.优化 #

11.1 observe # 

    constructor() {
        observe(this.todos,change => {
            console.log(change);
            this.disposers.forEach(disposer => disposer());
            this.disposers=[];
            for (let todo of change.object) {
                this.disposers.push(observe(todo,change => {
                    this.save();
                    //console.log(change)
                }));
            }
            this.save();
        });
    }

11.2 spy # 

spy(event => {
    //console.log(event);
})

11.3 toJS # 

    constructor() {
        observe(this.todos,change => {
            console.log(change);
            this.disposers.forEach(disposer => disposer());
            this.disposers=[];
            for (let todo of change.object) {
                this.disposers.push(observe(todo,change => {
                    this.save();
                    //console.log(change)
                }));
            }
            this.save();
        });
    }
    save() {
        localStorage.setItem('todos',JSON.stringify(toJS(this.todos)));
    }

11.4 trace # 

trace

12. 优化 #

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