Angular大量使用了JS的装饰器特性，先看

使用babel转换

1. npm install -g babel-cli
2. npm init; npm install --save-dev babel-plugin-transform-decorators-legacy
3. babel --plugins transform-decorators-legacy 1.js > 1.es5.js

例1

@eatclass Person {  constructor() {}}function eat(target, key, descriptor) {  console.log('吃饭');  console.log(target);  console.log(key);  console.log(descriptor);  target.prototype.act = '我要吃饭';}const jack = new Person();console.log(jack.act);

转换后

var _class;let Person = eat(_class = class Person {  constructor() {}}) || _class;function eat(target, key, descriptor) {  console.log('吃饭');  console.log(target);  console.log(key);  console.log(descriptor);  target.prototype.act = '我要吃饭';}const jack = new Person();console.log(jack.act);// 吃饭// [Function: Person]// undefined// undefined// 我要吃饭

例2

function mixins(...list) {  return function (target) {    Object.assign(target.prototype, ...list);  };}const Foo = {  foo() { console.log('foo') }};@mixins(Foo)class MyClass {}let obj = new MyClass();obj.foo() // "foo"

babel 后

var _dec, _class;function mixins(...list) {  return function (target) {    Object.assign(target.prototype, ...list);  };}const Foo = {  foo() {    console.log('foo');  }};let MyClass = (_dec = mixins(Foo), _dec(_class = class MyClass {}) || _class);let obj = new MyClass();obj.foo(); // "foo"