摘要：的按需加載方式中實(shí)現(xiàn)按需加載只需要按照下面代碼的方式實(shí)現(xiàn)就可以了。配置按需加載方式創(chuàng)建文件這個文件其實(shí)是個通過包裝后的組件來使用，下面會具體講這個東西。

介紹了在router4以后，如何去實(shí)現(xiàn)按需加載Component，在router4以前，我們是使用getComponent的的方式來實(shí)現(xiàn)按需加載的，router4中，getComponent方法已經(jīng)被移除，下面就介紹一下react-router4是入圍和來實(shí)現(xiàn)按需加載的。

route3中實(shí)現(xiàn)按需加載只需要按照下面代碼的方式實(shí)現(xiàn)就可以了。

const about = (location, cb) => {
    require.ensure([], require => {
        cb(null, require("../Component/about").default)
    },"about")
}

//配置route

創(chuàng)建Bundle.js文件,這個文件其實(shí)是個通過bundle-loader包裝后的組件來使用，下面會具體講這個東西。

import React from "react";
import PropTypes from "prop-types";

class Bundle extends React.Component {
  state = {
    // short for "module" but that"s a keyword in js, so "mod"
    mod: null
  }

  componentWillMount() {
    // 加載初始狀態(tài)
    this.load(this.props);
  }

  componentWillReceiveProps(nextProps) {
    if (nextProps.load !== this.props.load) {
      this.load(nextProps);
    }
  }

  load(props) {
    // 重置狀態(tài)
    this.setState({
      mod: null
    });
    // 傳入組件的組件
    props.load((mod) => {
      this.setState({
        // handle both es imports and cjs
        mod: mod.default ? mod.default : mod
      });
    });
  }

  render() {
    // if state mode not undefined,The container will render children
    return this.state.mod ? this.props.children(this.state.mod) : null;
  }
}

Bundle.propTypes = {
  load: PropTypes.func,
  children: PropTypes.func
};

export default Bundle;

import aContainer from "bundle-loader?lazy!./containers/A"

const A = (props) => (
  
      //這里只是給this.props.child傳一個方法，最后在Bundle的render里面調(diào)用
    {(Container) => }
  
)

 render() {
    return (
      

        
Welcome!
        
        
      
    )
  }

先看這段代碼：

module.exports = function (cb) {
    __webpack_require__.e/* require.ensure */(2).then((function (require) {
        cb(__webpack_require__(305));
    }).bind(null, __webpack_require__)).catch(__webpack_require__.oe);
};

這里是我們通過import loadDashboard from "bundle-loader?lazy!./containers/A"這種方式引入的container控件。我們使用了bundle-loader將A的源碼轉(zhuǎn)化成了上面的代碼，具體實(shí)現(xiàn)大家可以看bundle-loader源碼，代碼很少。

上面說到Bundle.js其實(shí)就使用來處理這個文件的，這個文件需要一個callback的參數(shù)，在Bundle的load方法中，我們會設(shè)置這個callback，當(dāng)路由要調(diào)到A Container這里的時候，就回去加載A Container,然后調(diào)用這個callback，這個callback會調(diào)用setState方法，將我們之前傳入的load設(shè)置給mod，然后渲染出來。

這里匹配的是src/routers/下面的containers文件夾下面所有的js文件，包括二級目錄。

  {
      // 匹配routers下面所有文件
      // ([^/]+)/?([^/]*) 匹配xxx/xxx 或者 xxx
      test: /containers/([^/]+)/?([^/]*).jsx?$/,
      include: path.resolve(__dirname, "src/routers/"),
      // loader: "bundle-loader?lazy"
      loaders: ["bundle-loader?lazy", "babel-loader"]
    }

/*
    MIT License http://www.opensource.org/licenses/mit-license.php
    Author Tobias Koppers @sokra
*/
var loaderUtils = require("loader-utils");

module.exports = function() {};
module.exports.pitch = function(remainingRequest) {
    this.cacheable && this.cacheable();
    var query = loaderUtils.getOptions(this) || {};
    if(query.name) {
        var options = {
            context: query.context || this.options.context,
            regExp: query.regExp
        };
        var chunkName = loaderUtils.interpolateName(this, query.name, options);
        var chunkNameParam = ", " + JSON.stringify(chunkName);
    } else {
        var chunkNameParam = "";
    }
    var result;
    if(query.lazy) {
        result = [
            "module.exports = function(cb) {
",
            "    require.ensure([], function(require) {
",
            "        cb(require(", loaderUtils.stringifyRequest(this, "!!" + remainingRequest), "));
",
            "    }" + chunkNameParam + ");
",
            "}"];
    } else {
        result = [
            "var cbs = [], 
",
            "    data;
",
            "module.exports = function(cb) {
",
            "    if(cbs) cbs.push(cb);
",
            "    else cb(data);
",
            "}
",
            "require.ensure([], function(require) {
",
            "    data = require(", loaderUtils.stringifyRequest(this, "!!" + remainingRequest), ");
",
            "    var callbacks = cbs;
",
            "    cbs = null;
",
            "    for(var i = 0, l = callbacks.length; i < l; i++) {
",
            "        callbacks[i](data);
",
            "    }
",
            "}" + chunkNameParam + ");"];
    }
    return result.join("");
}

/*
Output format:

    var cbs = [],
        data;
    module.exports = function(cb) {
        if(cbs) cbs.push(cb);
        else cb(data);
    }
    require.ensure([], function(require) {
        data = require("xxx");
        var callbacks = cbs;
        cbs = null;
        for(var i = 0, l = callbacks.length; i < l; i++) {
            callbacks[i](data);
        }
    });

*/

import React from "react";
import PropTypes from "prop-types";
import * as reactRedux from "react-redux";
import BaseContainer from "../../../containers/ReactBaseContainer";

class A extends BaseContainer {
  constructor(props) {
    super(props);
    this.renderCustom = function renderCustom() {
      return (
        

          Hello world In A
        
      );
    };
  }
  render() {
    // 返回父級view
    return super.render();
  }
}

A.propTypes = {
  dispatch: PropTypes.func,
};

function mapStateToProps(state) {
  return { state };
}

export default reactRedux.connect(mapStateToProps)(A);

import React from "react";
import { BrowserRouter, Switch, Link } from "react-router-dom";
import { Route } from "react-router";
import PostContainer from "../containers/PostsContainer";
// 設(shè)置trunk文件的名字  the basename of the resource
import aContainer from "./containers/A";
import bContainer from "./containers/B";
import cContainer from "./containers/C";
import Bundle from "../utils/Bundle";

const A = () => (
  
    {Component => }
  
)

const app = () =>
  

    {/* path = "/about" */}
    {/* "/about/" 可以，但"/about/1"就不可以了 exact 配置之后，需要路徑絕對匹配,多個斜杠沒有關(guān)系，這里直接在瀏覽器里面設(shè)置還有問題*/}
    {/* path = "/about/" */}
    {/* "/about/1" 可以，但"/about"就不可以了 用了strict，path要大于等于的關(guān)系，少一個斜杠都不行 */}
    {/* exact 和 strick 都用了就必須一模一樣，連斜杠都一樣 */}
     Link to about
    
    
    {/* 
     */}
  
;
export default function () {
  // 用來判斷本地瀏覽器是否支持刷新
  const supportsHistory = "pushState" in window.history;
  return (
    
      

        {app()}
      
    

  );
}

import React, { Component } from "react";

export default function asyncComponent(importComponent) {
  class AsyncComponent extends Component {
    constructor(props) {
      super(props);

      this.state = {
        component: null
      };
    }

    async componentDidMount() {
      const { default: component } = await importComponent();

      this.setState({
        component: component
      });
    }

    render() {
      const C = this.state.component;

      return C ?  : null;
    }
  }

  return AsyncComponent;
}

const Buttons = asyncComponent(() => import("./button"));

"presets": [
        [
          "es2015"
        ],
        "stage-1", // 應(yīng)用了es7的語法，所以必須有這個配置
        "react"
      ],

文章引用

http://henleyedition.com

react-router官方文檔