zoukankan      html  css  js  c++  java
  • [React] Use the URL as the source of truth in React

    In Single Page Apps we're used to fetch the data on event callbacks. That disables the capacity to use the URL to share it to someone else and get to the same state of the app, just like in non Single Page Apps.

    This lesson shows you how to use React and React Router to use the URL as the source of truth for your app state.

    Doing this in React, we can devide into three steps:

    1. We can use 'withRouter' HOC to get 'location' props.

    2. Handle refresh case: when page refresh, we want to check whether there is query string, if yes, then we need to fetch the data from the BE.

    3, Hnadle query string changes case: when the query string changes, we want to use 'componentWIllReceiveProps' lifecycle to get udpated query string, then fetch the data from BE.

    import React from "react";
    import { render } from "react-dom";
    import { withRouter } from "react-router";
    import { HashRouter, Route, Switch } from 'react-router-dom';
    import Search from "./Search";
    
    const styles = {
      fontFamily: "sans-serif",
      textAlign: "center"
    };
    
    // Step 1
    const App = withRouter(() => (
      <div style={styles}>
        <Switch>
          <Route exact path="/" component={Search} />
        </Switch>
      </div>
    ));
    
    render(
      <HashRouter>
        <App />
      </HashRouter>,
      document.getElementById("root")
    );
    
    
    -----------------------
    
    
    import React, { Component } from "react";
    
    const baseUrl = "https://jsonplaceholder.typicode.com/posts";
    
    class Hello extends Component {
      state = {
        results: []
      };
    
      // Step 2
      componentDidMount() {
        const queryString = this.props.location.search;
    
        if (queryString) {
          this.fetch(queryString);
        }
      }
    
      // Step 3
      componentWillReceiveProps({ location }) {
        const oldQueryString = this.props.location.search;
        const queryString = location.search;
    
        if (oldQueryString !== queryString) {
          this.fetch(queryString);
        }
      }
    
      fetch = (queryString = "") => {
        fetch(`${baseUrl}${queryString}`)
          .then(res => res.json())
          .then(results => this.setState({ results }));
      };
    
      handleChange = ev => {
        const { value } = this.input;
        const queryString = value ? `?q=${value}` : "";
        const currentUrl = window.location.href.split("?")[0];
        window.location = `${currentUrl}${queryString}`;
      };
    
      render() {
        return (
          <div>
            <input ref={input => (this.input = input)} onBlur={this.handleChange} />
            <br />
            {this.state.results.map((res, i) => <p key={i}>{res.title}</p>)}
          </div>
        );
      }
    }
    
    export default Hello;
  • 相关阅读:
    生物神经网络和人工神经网络浅谈
    卷积神经网络
    DOM进阶之HTMl属性操作(对象属性)
    01 selenium基本使用补充
    01 selenium基本使用
    day4笔记
    03 获取豆瓣电影top250
    02 爬取视频
    day3笔记
    01 requests基本使用
  • 原文地址:https://www.cnblogs.com/Answer1215/p/7794432.html
Copyright © 2011-2022 走看看