数组迭代，对象迭代
作者：互联网
遍历器（Iterator）是一种机制(接口)：为各种不同的数据结构提供统一的访问机制，任何数据结构只要部署Iterator接口，就可以完成遍历操作「for of循环」，依次处理该数据结构的所有成员
* + 拥有next方法用于依次遍历数据结构的成员
* + 每一次遍历返回的结果是一个对象 {done:false,value:xxx}
* + done:记录是否遍历完成
* + value:当前遍历的结果
*
* 拥有Symbol.iterator属性的数据结构(值)，被称为可被遍历的，可以基于for of循环处理
* + 数组
* + 部分类数组：arguments/NodeList/HTMLCollection...
* + String
* + Set
* + Map
* + generator object
* + ...
} let itor = new Iterator([10, 30, 20, 40]) console.log(itor.next()); console.log(itor.next()); console.log(itor.next()) console.log(itor.next()) console.log(itor.next()) 对象迭代 let obj = { name: 'zhufeng', age: 12, teacher:'team' } //obj[Symbol.iterator] Object.prototype[Symbol.iterator] = function () { let assemble = this, keys = Object.keys(assemble).concat(Object.getOwnPropertySymbols(assemble)), index = 0; return { next() { if (index > keys.length - 1) { return { done: true, value: undefined }; } return { done: false, value:assemble[keys[index++]] } } } } for (let value of obj) { console.log(value) 浏览器展示如下： }
对象迭代：
let obj = {
name: 'zhufeng',
age: 12,
teacher:'team'
}
//obj[Symbol.iterator] 可以给对象添加属性[Symbol.iterator]也可以给对象原型添加属性[Symbol.iterator]
Object.prototype[Symbol.iterator] = function () {
let assemble = this,
keys = Object.keys(assemble).concat(Object.getOwnPropertySymbols(assemble)),
index = 0;
return {
next() {
if (index > keys.length - 1) {
return {
done: true,
value: undefined
};
}
return {
done: false,
value:assemble[keys[index++]]
}
}
}
}
for (let value of obj) {
console.log(value)
}
浏览器输出：
数组迭代
class Iterator{ constructor(assemble) { let self = this; self.assemble = assemble; self.index = 0 } next() { let self = this, assemble = self.assemble; if (self.index > assemble.length - 1) { return { done: true, value:undefined } } return { done: false, value:this.assemble[self.index++] } }} let itor = new Iterator([10, 30, 20, 40]) console.log(itor.next()); console.log(itor.next()); console.log(itor.next()) console.log(itor.next()) console.log(itor.next()) 对象迭代 let obj = { name: 'zhufeng', age: 12, teacher:'team' } //obj[Symbol.iterator] Object.prototype[Symbol.iterator] = function () { let assemble = this, keys = Object.keys(assemble).concat(Object.getOwnPropertySymbols(assemble)), index = 0; return { next() { if (index > keys.length - 1) { return { done: true, value: undefined }; } return { done: false, value:assemble[keys[index++]] } } } } for (let value of obj) { console.log(value) 浏览器展示如下： }
对象迭代：
let obj = {
name: 'zhufeng',
age: 12,
teacher:'team'
}
//obj[Symbol.iterator] 可以给对象添加属性[Symbol.iterator]也可以给对象原型添加属性[Symbol.iterator]
Object.prototype[Symbol.iterator] = function () {
let assemble = this,
keys = Object.keys(assemble).concat(Object.getOwnPropertySymbols(assemble)),
index = 0;
return {
next() {
if (index > keys.length - 1) {
return {
done: true,
value: undefined
};
}
return {
done: false,
value:assemble[keys[index++]]
}
}
}
}
for (let value of obj) {
console.log(value)
}
浏览器输出：
标签：index,return,迭代,对象,value,next,let,数组,assemble 来源： https://www.cnblogs.com/zhx119/p/14401884.html