React Component的constructor内为何不可以直接定义this.变量（除了this.state外）

Question

报了这个错误：Property 'store' does not exist on type 'PageDemo'. TS2339

大伙帮看看

import React, { Component } from 'react';
import {inject, observer} from "mobx-react"; 

@inject('store') @observer
class PageDemo extends Component<any, any> {
    constructor(props:any) {
        super(props)
        this.store = props.store.demoStore // 报错行
        this.state = { // 这样就不会报错
            store: props.store.exampleStore
        }
    }

    render() {
        const {text, num} = this.state.store
        return (
            <div className="main">
                
            </div>
        );
    }
}

export default PageDemo;

Answer 1

你的问题是typescript问题,在使用一个属性前需要先定义

import React, { Component } from 'react';
import {inject, observer} from "mobx-react"; 

@inject('store') @observer
class PageDemo extends Component<any, any> {
    //为PageDemo定义一个store属性
    public store: any
    constructor(props:any) {
        super(props)
        this.store = props.store.demoStore // 报错行
        this.state = { // 这样就不会报错
            store: props.store.exampleStore
        }
    }

    render() {
        const {text, num} = this.state.store
        return (
            <div className="main">
                
            </div>
        );
    }
}

export default PageDemo;