const button = document.createElement('button');
button.innerHTML = '关注 webyouxuan';
document.body.appendChild(button);
document.addEventListener('click',()=>{
    import('./a').then(data=>{
        console.log(data.default);
    })
});

(window["webpackJsonp"] = window["webpackJsonp"] || []).push([
  ["src_a_js"],
  {
    "./src/a.js": module => {
      eval(
        "module.exports = 'webyouxuan'\n\n//# sourceURL=webpack:///./src/a.js?"
      );
    }
  }
]);

"./src/index.js":
 ((__unusedmodule, __unusedexports, __webpack_require__) => {
eval(`
    const button = document.createElement('button');
    button.innerHTML = '关注 webyouxuan';
    document.body.appendChild(button);
    document.addEventListener('click',()=>{
       __webpack_require__.e("src_a_js").then(
          __webpack_require__.t.bind(__webpack_require__, "./src/a.js", 7)).then(data=>{
            console.log(data.default);
          })
     })
    `);
 })

__webpack_require__.f = {};
__webpack_require__.e = (chunkId) => { // chunkId => src_a_js动态加载的模块
    return Promise.all(Object.keys(__webpack_require__.f).reduce((promises, key) => {
        __webpack_require__.f[key](chunkId, promises); // 调用j方法 将数组传入
        return promises;
    }, []));
};
var installedChunks = {
    "main": 0 // 默认main已经加载完成
};
// f方法上有个j属性
__webpack_require__.f.j = (chunkId, promises) => {
    var installedChunkData = Object.prototype.hasOwnProperty.call(installedChunks, chunkId) ? installedChunks[chunkId] : undefined;
    if(installedChunkData !== 0) {  // 默认installedChunks肯定没有要加载的模块
        if(installedChunkData) {
            promises.push(installedChunkData[2]);
        } else {
            if(true) { // 创建一个promise 把当前的promise 成功失败保存到 installedChunks
                var promise = new Promise((resolve, reject) => {
                    installedChunkData = installedChunks[chunkId] = [resolve, reject];
                });
                // installedChunks[src_a_js] = [resolve,reject,promise]
                promises.push(installedChunkData[2] = promise);
                // 这句的意思是看是否配置publicPath，配置了就加个前缀
                var url = __webpack_require__.p + __webpack_require__.u(chunkId);
                // 1)创建script标签
                var script = document.createElement('script');
                var onScriptComplete;
                script.charset = 'utf-8';
                script.timeout = 120;
                script.src = url; // 2)开始加载这个文件
                var error = new Error();
                onScriptComplete = function (event) { //  完成工作
                    script.onerror = script.onload = null;
                    clearTimeout(timeout);
                    var reportError = loadingEnded();
                    if(reportError) {
                        var errorType = event && (event.type === 'load' ? 'missing' : event.type);
                        var realSrc = event && event.target && event.target.src;
                        error.message = 'Loading chunk ' + chunkId + ' failed.\n(' + errorType + ': ' + realSrc + ')';
                        error.name = 'ChunkLoadError';
                        error.type = errorType;
                        error.request = realSrc;
                        reportError(error);
                    }
                };
                var timeout = setTimeout(function(){ // 超时工作
                    onScriptComplete({ type: 'timeout', target: script });
                }, 120000);
                script.onerror = script.onload = onScriptComplete;
                document.head.appendChild(script); // 3)将标签插入到页面
            } else installedChunks[chunkId] = 0;
        }
    }
};

(window["webpackJsonp"] = window["webpackJsonp"] || []).push([
  ["src_a_js"],
  {
    "./src/a.js": module => {
      eval(
        "module.exports = 'webyouxuan'\n\n//# sourceURL=webpack:///./src/a.js?"
      );
    }
  }
]);

function webpackJsonpCallback(data) { // 3) 文件加载后会调用此方法
    var chunkIds = data[0]; // data是什么来着，你看看src_a_js怎么写的你就知道了 看上面！ ["src_a_js"]
    var moreModules = data[1]; // 获取新增的模块
    var moduleId, chunkId, i = 0, resolves = [];
    for(;i < chunkIds.length; i++) {
        chunkId = chunkIds[i];
        if(Object.prototype.hasOwnProperty.call(installedChunks, chunkId) && installedChunks[chunkId]) {
            // installedChunks[src_a_js] = [resolve,reject,promise] 这个是上面做的
            // 很好理解 其实就是取到刚才放入的promise的resolve方法
            resolves.push(installedChunks[chunkId][0]);
        }
        installedChunks[chunkId] = 0; // 模块加载完成
    }
    for(moduleId in moreModules) { // 将新增模块与默认的模块进行合并 也是就是modules模块，这样modules中就多了动态加载的模块
        if(Object.prototype.hasOwnProperty.call(moreModules, moduleId)) {
            __webpack_require__.m[moduleId] = moreModules[moduleId];
        }
    }
    if(runtime) runtime(__webpack_require__);
    if(parentJsonpFunction) parentJsonpFunction(data);
    while(resolves.length) { // 调用promise的resolve方法，这样e方法就调用完成了
        resolves.shift()();
    }
};
var jsonpArray = window["webpackJsonp"] = window["webpackJsonp"] || []; // 1) window["webpackJsonp"]等于一个数组
var oldJsonpFunction = jsonpArray.push.bind(jsonpArray);
jsonpArray.push = webpackJsonpCallback; // 2) 重写了数组的push方法
var parentJsonpFunction = oldJsonpFunction;

__webpack_require__.t = function(value, mode) { // t方法其实很简单就是
    if(mode & 1) value = this(value); // 就是调用__webpack_require__加载最新的模块
};