js中现在比较成熟的模块加载方案（js模块加载机制）

//math.jsmodule.exports.add = (x, y) => x + y;//program.jsvar math = require(\\\'math\\\');math.add(1,2)

define(id?, dependencies?, factory)

//定义模块 demo.jsdefine(function(){  var exports = {};  exports.sayHello = function(){    alert(\\\'Hello from module:\\\' + module.id)  }  return exports;})//使用requite(\\\'demo\\\',function(demo){  demo.sayHello(); });

//模块 user.jslet name = \\\'cuishunbiao\\\';let sex = \\\'男\\\';let work = \\\'web\\\';export {  name,  sex,  work}//main.jsimport {name,sex,work} from \\\'./user.js\\\'console.log(name,sex,work);

// lib.jsvar counter = 1;function addCounter(){  counter++}module.exports = {  counter: counter,  addCounter: addCounter}
//main.jsvar counter = require(\\\'./lib\\\').counter;var addCounter = require(\\\'./lib\\\').addCounter;console.log(counter);//1addCounter();console.log(counter);//1 输出值不受影响

//lib.jsexport let counter = 1;export function addCounter(){  counter++}//main.jsimport {counter,addCounter} from \\\'./lib\\\';console.log(counter);//1addCounter();console.log(counter);//2 改变了输出值

;(function (name, definition) {  // 检测上下文环境是否为AMD或CMD  var hasDefine = typeof define === \\\'function\\\',    // 检查上下文环境是否为Node    hasExports = typeof module !== \\\'undefined\\\' && module.exports;
  if (hasDefine) {    // AMD环境或CMD环境    define(definition);  } else if (hasExports) {    // 定义为普通Node模块    module.exports = definition();  } else {    // 将模块的执行结果挂在window变量中，在浏览器中this指向window对象    this[name] = definition();  }})(\\\'hello\\\', function () {  var hello = function () {};  return hello;});