否有中间的调度中心。
class EventBus { constructor () { this.events = Object.create(null) } on (event, fn) { this.events.event = this.events.event || [] this.events.event.push(fn) } off (event, fn) { const index = (this.events.event || []).indexOf(fn) if (index < -1) { return } else { this.events.event.splice(index, 1) } } fire (event) { this.events.event.forEach(fn => fn()) } } var bus = new EventBus() bus.on(‘onclick‘, function () { console.log(‘click1 fire‘) }) bus.on(‘onclick‘, fn=function () { console.log(‘click2 fire‘) }) bus.fire(‘onclick‘)
class Observer { constructor (fn) { this.update = fn } } class Subject { constructor () { this.observers = [] } addObserver (observer) { this.observers.push(observer) } removeObserver (observer) { const delIndex = this.observers.indexOf(observer) this.observers.splice(delIndex, 1) } notify () { this.observers.forEach(observer => { observer.update() }) } } var subject = new Subject() var ob1 = new Observer(function () { console.log(‘ob1 callback run‘) }) subject.addObserver(ob1) var ob2 = new Observer(function () { console.log(‘ob2 callback run‘) }) subject.addObserver(ob2) subject.notify()
// 防抖，在一定事件内，多次触发事件，会重新计算时间进行执行
// 防抖 input 校验 模糊搜索 resize
function debounce (fn,delay) {
// 记录上一次的延时器
var timer = null;
return function () {
// 清除上一次的延时器
clearTimeout(timer);
// 重新设置新的延时器
timer = setTimeout(function () {
fn.apply(this);
},delay)
}
}
function throttle (fn, delay) {
var lastTime = 0;
return function () {
var nowTime = Date.now();
if (nowTime - lastTime > delay) {
fn.call(this);
lastTime = nowTime;
}
}
}
一：JSON.parse(JSON.toString(obj)); // 无法拷贝内置方法
二
function deepCopy (obj) {
let result = obj;
if (typeof(obj) === ‘string‘ && obj !== null) {
result = Object.prototype.toString.call(obj) === ‘[object Array]‘ ? [] : {};
for (let prop in obj) {
result[prop] = deepCopy(obj[prop]);
}
}
return result;
}
var obj = {
name: ‘xiao‘,
age: 24,
run :{
function () {
console.log(1)
}
}
};
function deepCopy (obj) {
// 排除null
if (obj === null) {
return null;
}
// 判断是数组还是对象
var result = Array.isArray(obj) ? [] : {};
// 循环
for (let key in obj) {
// 判断属性是否存在
if(obj.hasOwnProperty(key)) {
if (typeof obj[key] === ‘object‘) {
// 如果还是对象，再次调用此方法
result[key] = deepCopy(obj[key]);
} else {
result[key] = obj[key]
}
}
}
}
var arr =[1,2,3,4,5,2,3]; var arr1 = [... new Set(arr)]
var arr = [1,2,3,4,2,1];
var arr1 = arr.reduce(function(ar, item){
if (!ar.includes(item)) {
ar.push(item);
}
return ar;
},[]);
function reverse(str) {
return str
.split(‘‘)
.reverse()
.join(‘‘)
}
console.log(reverse(str));
var ary=[1,4,7,8,12,34,67,88,99,100]
function getIndex(arr,num) {
var len = arr.length;
var st = 0;
var end = len-1;
while(str<end){
var mid = Math.floor((st+end)/2);
if (num = arr[mid]) {
return mid;
} else if (num > arr[mid]) {
st = mid +1;
} else {
end = mid-1;
}
}
}
// 冒泡排序
//从小到大
function BubbleSort(arr){
var i,j,temp;
for(i=0;i<arr.length-1;i++){
for(j=i+1;j<arr.length;j++){
if(arr[i]>arr[j]){
temp=arr[j];
arr[j]=arr[i];
arr[i]=temp;
}
}
}
return arr;
}
var arr=[10,7,9,11,22,33,4,2,0,1000];
BubbleSort(arr);
console.log(arr); //[0, 2, 4, 7, 9, 10, 11, 22, 33, 1000]
function a() {
this.name = ‘张三‘;
}
a.prototype.getName = function() {
return this.name;
}
var instance = new a();
console.log(instance.getName());//‘张三‘
原文：https://www.cnblogs.com/jcxfighting/p/11668343.html