前方高能預警，請你做好迎戰準備,一大js手寫程式碼實現正向你襲來。
1.call
Object.prototype.myCall = function (context, ...params) {
if (typeof this !== 'function') {
throw TypeError('holp caller is functiom')
}
let fn = Symbol('fn')
let obj = context || window
obj[fn] = this
let res = obj[fn](...params)
delete obj[fn]
return res
}
複製程式碼2.apply
Object.prototype.myApply = function (context, params = []) {
if (typeof this !== 'function') {
throw TypeError('holp caller is functiom')
}
let fn = Symbol('fn')
let obj = context || window
obj[fn] = this
let res = obj[fn](...params)
delete obj[fn]
return res
}
複製程式碼3.bind
Object.prototype.myBind = function (context, ...arg) {
if (typeof this !== 'function') {
throw TypeError('holp caller is functiom')
}
let obj = context || window
return (...arg2) => {
this.call(obj, ...arg, ...arg2)
}
}
複製程式碼4.instanceOf
function instance(L, R) {
let l = L.__proto__
let r = R.prototype
while (true) {
if (l === null) return false
if (l === r) return true
l = l.__proto__
}
}
複製程式碼5.Objeact.create
function create(obj) {
function F() { }
F.prototype = obj
return new F()
}
複製程式碼6.promise
function myPromise(constructor) {
let that = this
this.status = 'pendding'
this.succVal = ''
this.errVal = ''
function resovle(val) {
if (that.status === 'pendding') {
that.succVal = val
that.status = 'resolved'
}
}
function reject(val) {
if (that.status === 'pendding') {
that.errVal = val
that.status = 'rejected'
}
}
try {
constructor(resovle, reject)
} catch (error) {
reject(error)
}
}
myPromise.prototype.then = function (succFn, errFn) {
let that = this
switch (that.status) {
case 'resolved': succFn(that.succVal)
break
case 'rejected': errFn(that.errVal)
break
}
}
複製程式碼7.new
function myNew(context, ...params) {
let obj = Object.create(context.prototype)
let res = context.apply(obj, params)
return typeof res === 'object' ? res : obj
}
複製程式碼8.深拷貝
function deepClone(p, c) {
for (let prop in p) {
if (typeof p[prop] === 'object') {
c[prop] = p[prop] instanceof Array ? [] : {}
deepClone(p[prop], v[prop])
} else {
c[prop] = p[prop]
}
}
}
複製程式碼9.es5繼承
function Animal(name) {
this.name = name
}
Animal.prototype.sayName = function () {
console.log(this.name)
}
function Dog(name, age) {
Animal.call(this, name)
this.age = age
}
Dog.prototype = Object.create(Animal.prototype)
Dog.prototype.constructor = "Dog"
Dog.prototype.sayAge = function () {
console.log(this.age)
}
複製程式碼10.二分查詢
function binarySearch(arr, start, end, value) {
if (start > end) {
return -1
}
let middle = parseInt((start + end) / 2)
if (value < arr[middle]) {
end = middle + 1
return binarySearch(arr, start, end, value)
} else if (value > arr[middle]) {
start = middle - 1
return binarySearch(arr, start, end, value)
} else if (value === arr[middle]) {
return middle
}
}
複製程式碼11.快排
function quickSort(arr) {
if (arr.length <= 1) { return arr; }
let middle = Math.floor(arr / 2)
let value = arr.splice(middle, 1)[0]
let left = [], right = []
for (let i = 0; i < arr.length; i++) {
if (arr[i] > value) {
right.push(arr[i])
} else if (arr[i] < value) {
left.push(arr[i])
}
}
return quickSort(left).concat([value], quickSort(right))
}
複製程式碼12.氣泡排序
function bubbleSort(arr) {
let len = arr.length
let temp
for (let i = 0; i < len; i++) {
for (let j = i + 1; j < len; j++) {
if (arr[i] < arr[j]) {
temp = arr[i]
arr[i] = arr[j]
arr[j] = temp
}
}
}
return arr
}
複製程式碼13.選擇排序
function selectSort(arr) {
let len = arr.length
let minIndex, temp
for (let i = 0; i < len; i++) {
minIndex = i
for (let j = i + 1; j < len; j++) {
if (arr[minIndex] > arr[j]) {
minIndex = j
}
}
temp = arr[minIndex]
arr[minIndex] = arr[i]
arr[i] = temp
}
return arr
}
複製程式碼14.原生Ajax
let xhr = new XMLHttpRequest()
xhr.open(Get,'xxx.js',false)
xhr.onreadystatechange = function () {
if (xhr.status === 200 && xhr.readyState === 4) {
console.log(xhr.responseText)
}
}
複製程式碼15.訂閱釋出模式
let Observer = (function () {
let __msg = {}
return {
register: function (type, fn) {
if (typeof __msg[type] === 'undefined') {
__msg[type] = [fn]
} else {
__msg[type].push(fn)
}
},
dispatch: function (type, args) {
if (!__msg[type]) return
let len = __msg[type].length
let params = { type, args }
for (let i = 0; i < len; i++) {
__msg[type][i].call(this, params)
}
},
remove: function (type, fn) {
if (__msg[type] instanceof Array) {
let len = __msg[type].length - 1
for (let i = len; i >= 0; i--) {
__msg[type][i] === fn && __msg[type].splice(i, 1)
}
}
}
}
})()
複製程式碼16.斐波那契演算法
function fibo(n) {
if (n === 1 || n === 2) {
return 1
}
return fibo(n - 2) + fibo(n - 1)
}
複製程式碼17.去重
function questStep(arr) {
let key = {}
let value = []
arr.forEach(element => {
if (!(element in key)) {
key[element] = true
value.push(element)
}
})
return value
}
複製程式碼18.防抖
let antiShake = function () {
let timer = null
return function () {
timer && clearTimeout(timer)
timer = setTimeout(() => {
console.log('防抖成功')
timer = null
}, 2000)
}
}
複製程式碼19.節流
function throttle() {
let timer = null
return () => {
if (!timer) {
timer = setTimeout(() => {
console.log('節流成功')
timer = null
}, 2000)
}
}
}
複製程式碼20.雙向繫結
function bothwayBind(fromKey, container, obj, key) {
Object.defineProperty(obj, key, {
set(val) {
fromKey.value = val
container.innerHTML = val
}
})
fromKey.onkeyup = function (e) {
obj[key] = e.target.value
}
}
複製程式碼