### 函数分时加载：间隔200ms执行一次渲染函数
```
let arr = []
for(let i = 0; i < 1000; i++) {
arr.push(i)
}
function timeout(arg, fn, count) {
var timer, data;
function start() {
for(let i = 0; i < Math.min( count || arg.length ); i++) {
data = arg.shift()
fn(data)
}
}
return function() {
timer = setInterval(function() {
console.log('in')
if (!arg.length) {
return clearInterval(timer)
}
start()
}, 200)
}
}
let render = timeout(arr, function(data) {
let div = document.createElement('div')
div.innerHTML = data
document.body.appendChild( div )
}, 8)
render()
```
### 函数节流：500ms执行一次onmouse事件
```
let div = document.querySelector('div')
function water(fn, delay) {
var timer, firstTime = true, _fn = fn;
return function() {
const _this = this
const arg = arguments;
if (firstTime) {
_fn.apply(_this, arg)
return firstTime = false;
}
if (timer) {
return false
}
timer = setTimeout(function() {
clearTimeout(timer)
timer = null
_fn.apply(_this, arg)
}, delay || 500)
}
}
div.onmousemove = water(function() {
console.log('1')
}, 500)
```
### 1. 单例模式
```
function Single(name) {
this.name = name
this.instance = null
}
Single.prototype = {
constructor: Single,
getInstance(name) {
if (!this.instance) {
this.instance = new Single(name)
}
return this.instance
}
}
const obj = Single.prototype.getInstance('Jack')
const obj2 = Single.prototype.getInstance()
console.log(obj.name)
console.log(obj2.name)
```
### 惰性单例
```
let div = document.querySelector('div')
function createDom() {
let instance = null;
return function() {
if (!instance) {
instance = document.createElement('div')
instance.style.width = '300px'
instance.style.height = '300px'
instance.style.background = 'skyblue'
instance.style.display = 'none'
document.body.appendChild( instance )
}
console.log(instance, 'test')
return instance
}()
}
div.onclick = function() {
let dom = createDom()
dom.style.display = 'block'
}
```
