//虚拟 dom
{
class VNode {
constructor(tag, children, text) {
this.tag = tag;
this.text = text;
this.children = children;
}
render() {
if (this.tag === "#text") {
return document.createTextNode(this.text);
}
let el = document.createElement(this.tag);
this.children.forEach(vChild => {
el.appendChild(vChild.render());
});
return el;
}
}
function v(tag, children, text) {
if (typeof children === "string") {
text = children;
children = [];
}
return new VNode(tag, children, text);
}
let vNodes = v("div", [
v("p", [v("span", [v("#text", "xiedaimala.com")])]),
v("span", [v("#text", "jirengu.com")])
]);
function patchElement(parent, newVNode, oldVNode, index = 0) {
if (!oldVNode) {
parent.appendChild(newVNode.render());
} else if (!newVNode) {
parent.removeChild(parent.childNodes[index]);
} else if (newVNode.tag !== oldVNode.tag || newVNode.text !== oldVNode.text) {
parent.replaceChild(newVNode.render(), parent.childNodes[index]);
} else {
for (
let i = 0; i < newVNode.children.length || i < oldVNode.children.length; i++) {
patchElement(parent.childNodes[index], newVNode.children[i], oldVNode.children[i], i);
}
}
}
let vNodes1 = v("div", [
v("p", [v("span", [v("#text", "美国)])]),
v("span", [v("#text", "拉斯维加斯")])
]);
let vNodes2 = v("div", [
v("p", [v("span", [v("#text", "美国)])]),
v("span", [v("#text", "圣安地列斯"), v("#text", "佛罗里达")])
]);
}
Function.prototype.myCall = function(context) {
var context = context || window;
// 给 context 添加一个属性
// getValue.call(a, 'yck', '24') => a.fn = getValue
context.fn = this;
// 将 context 后面的参数取出来
var args = [...arguments].slice(1);
// getValue.call(a, 'yck', '24') => a.fn('yck', '24')
var result = context.fn(...args);
// 删除 fn
delete context.fn;
return result;
};Function.prototype.myApply = function(context) {
var context = context || window;
context.fn = this;
var result;
// 需要判断是否存储第二个参数
// 如果存在，就将第二个参数展开
if (arguments[1]) {
result = context.fn(...arguments[1]);
} else {
result = context.fn();
}
delete context.fn;
return result;
};Function.prototype.myBind = function(context) {
if (typeof this !== "function") {
throw new TypeError("Error");
}
var _this = this;
var args = [...arguments].slice(1);
// 返回一个函数
return function F() {
// 因为返回了一个函数，我们可以 new F()，所以需要判断
if (this instanceof F) {
return new _this(...args, ...arguments);
}
return _this.apply(context, args.concat(...arguments));
};
};function debounce(fn, delay) {
let timerId = null;
return function() {
const context = this;
if (timerId) {
window.clearTimeout(timerId);
}
timerId = setTimeout(() => {
fn.apply(context, arguments);
timerId = null;
}, delay);
};
}
const debounced = debounce(() => console.log("hi"));function throttle(fn, delay) {
let canUse = true;
return function() {
if (canUse) {
fn.apply(this, arguments);
canUse = false;
setTimeout(() => (canUse = true), delay);
}
};
}
const throttled = throttle(() => console.log("hi"));
throttled();function deepClone(obj) {
function isObj(obj) {
return ( (typeof obj === "object" || typeof obj === "function") && typeof obj !== null );
}
if (!isObj(obj)) {
throw new Error("not Object");
}
let isArray = Array.isArray(obj);
let newObj = isArray ? [...obj] : { ...obj };
Reflect.ownKeys(newObj).forEach(key => {
newObj[key] = isObj(obj[key]) ? deepClone(obj[key]) : obj[key];
});
return newObj;
}function flatten(origin) {
while (origin.some(item => Array.isArray(item))) {
origin = [].concat(...origin);
}
return origin;
} function delegate(element, eventType, selector, fn) {
element.addEventListener(eventType, e => {
let el = e.target
while (!el.matches(selector)) {
if (element === el) {
el = null
break
}
el = el.parentNode
}
el && fn.call(el, e, el)
})
return element
}function quickSort(arr) {
const pivot = arr.shift();
const left = [];
const right = [];
if (arr.length < 2) {
return arr;
}
arr.forEach(element => {
element < pivot ? left.push(element) : right.push(element);
});
return quickSort(left).concat([pivot], quickSort(right));
}
test const arr = [91, 60, 96, 7, 35, 65, 10, 65, 9, 30, 20, 31, 77, 81, 24];function bubbleSort(arr) {
var len = arr.length;
for (var i = 0; i < len; i++) {
for (var j = 0; j < len - 1 - i; j++) {
if (arr[j] > arr[j+1]) {
var temp = arr[j+1];
arr[j+1] = arr[j];
arr[j] = temp;
}
}
}
return arr;
}function selectionSort(arr) {
var minIndex, temp;
for (var i = 0; i < arr.length; - 1; i++) {
minIndex = i;
for (var j = i + 1; j < len; j++) {
if (arr[j] < arr[minIndex]) { //寻找最小的数
minIndex = j; //将最小数的索引保存
}
}
temp = arr[i];
arr[i] = arr[minIndex];
arr[minIndex] = temp;
}
return arr;
}function insertionSort(arr) {
for(let i = 1; i < arr.length; i++) {
for(let j = 0; j < i; j++) {
if(arr[i] < arr[j]) {
arr.splice(j, 0, arr[i])
arr.splice(i+1, 1)
break
}
console.log(arr)
}
}
}function bucketSort(arr) {
if (Object.prototype.toString.call(arr).toLowerCase() !== '[object array]') {
console.error('Function bucketSort got incorrect argument')
return
}
// 声明一个空桶, 将数据压入桶中
const bucket = []
arr.forEach((one) => {
if (bucket[one] !== undefined) {
bucket[one]++
} else {
bucket[one] = 1
}
});
// 声明一个新数组, 当做排序后的数组
const newArr = []
bucket.forEach((one, index) => {
if (one !== undefined) {
for (let i = 0; i < one; i++) {
newArr.push(index)
}
}
})
return newArr
}let array = [12, 9, 3, 7, 5, 6, 11, 2, 12, 32, 45];
var twoSum = function(arr, target) {
var a = {}
for (var i = 0; i < arr.length; i++) {
var tmp = target - arr[i]
if (a[tmp]) {
return [a[tmp], i]
}
a[arr[i]] = i
}
}
console.log(twoSum(array,8))