import '../css/detail.css';// 找到字符串中重復次數(shù)最多的字符 function findMax(str) {let maxChar = '';let maxValue = 1;if (!str.length) return;let arr = str.replace(/\s/g, '').split('');let obj = {};for (let i = 0; i < arr.length; i++) {if (!obj[arr[i]]) {obj[arr[i]] = 1;} else {obj[arr[i]]++;}}let keys = Object.keys(obj);for (let j = 0; j < keys.length; j++) {if (obj[keys[j]] > maxValue) {maxValue = obj[keys[j]];maxChar = keys[j];}}return {maxChar, maxValue} }function findMax1() {let maxChar = '';let maxValue = 1;let h = {};if (!str.length) return;let arr = str.replace(/\s/g, '').split('');for (let i = 0; i < arr.length; i++) {let a = arr[i];h[a] === undefined ? h[a] = 1 : h[a]++;if (h[a] > maxValue) {maxChar = a;maxValue = h[a];}}return {maxChar, maxValue} }function findMax2() {let maxChar = '';let maxValue = 1;if (!str.length) return;let arr = str.replace(/\s/g, '').split('');let obj = arr.reduce((acc, curVal) => {acc[curVal] ? acc[curVal]++ : acc[curVal] = 1;if (acc[curVal] > maxValue) {maxChar = curVal;maxValue = acc[curVal];}return acc;}, {}) return {maxChar, maxValue} } /* \d 任意一個數(shù)字，0~9 中的任意一個\w 任意一個字母或數(shù)字或下劃線，也就是 A~Z,a~z,0~9,_ 中任意一個\s 包括空格、制表符、換頁符等空白字符的其中任意一個 . 小數(shù)點可以匹配除了換行符（\n）以外的任意一個字符 */ function findMax3(str) {let maxChar = '';let maxValue = 1;if (!str.length) return;let arr = str.replace(/\s/g, '').split('');let obj = {};str.replace(/\s/g, '').replace(/(\w)/g, (word, p) => {obj[p] ? obj[p]++ : obj[p] = 1;if (obj[p] > maxValue) {maxValue = obj[p];maxChar = p;}});return {maxChar, maxValue}}function findMax4(str) {let maxChar = '';let maxValue = 1;if (!str.length) return;let arr = str.replace(/\s/g, '').split('');Array.prototype.getMost = function() {let obj = this.reduce((acc, cur) => {acc[cur] ? acc[cur]++ : acc[cur] = 1;acc.max = acc[cur] > acc.max ? acc[cur] : acc.max;acc.key = acc[cur] > acc.max ? cur : acc.key;return acc;}, {});return obj;}// return arr.getMost(); }const str = 'this is a test 222222 ts project. skajdf; 222sldjfwel p' const reducer = (accumulator, currentValue, b, c) => {let obj = {};obj[b] = currentValue;return obj; } const array1 = [1, 2, 3, 4]; // console.log(array1.reduce(reducer));console.log(findMax(str)); console.log('findMax1', findMax4(str)); /*** 輸入一個整形數(shù)組，數(shù)組里有正數(shù)也有負數(shù)。數(shù)組中連續(xù)的一個或多個整數(shù)組成一個子數(shù)組，每個子數(shù)組都有一個和。 求所有子數(shù)組的和的最大值，要求時間復雜度為O(n)。*/ function findMaxSubArr(arr) {console.log(arr)let max = arr[0];let currSum = 0;for (let i = 0; i < arr.length; i++) {if (currSum < 0) {currSum = arr[i];} else {currSum += arr[i]; }if (currSum > max) {max = currSum;}}return max; }// console.log('maxsubarr', findMaxSubArr([1, -2, 3, 10, -4, 7, 2, -5])); // 輸出結(jié)果 console.log('begin'); setTimeout(() => {console.log('settimeout 1')Promise.resolve().then( () => {console.log('promise 1')setTimeout(() => {console.log('settimeout 2');});}).then(() => {console.log('promise 2');}) }, 0); console.log('end'); /*** 類數(shù)組轉(zhuǎn)成數(shù)組*/ const nodes = document.querySelectorAll('div'); // nodes.map(item => {});// 1.for直接遍歷// 2.這種方法是借用了數(shù)組原型中的slice方法，返回一個數(shù)組 Array.prototype.slice.call(nodes).map(item => {}); [].slice.call(nodes).map(item => {console.log()});// 3.Array.from() 方法從一個類似數(shù)組或可迭代對象中創(chuàng)建一個新的數(shù)組實例。 Array.from(nodes).map(item => {})// 4.同樣是ES6中新增的內(nèi)容，擴展運算符（…）也可以將某些數(shù)據(jù)結(jié)構(gòu)轉(zhuǎn)為數(shù)組 const nodeList = [...nodes]; function getlist(a,b,c,d) {// console.log(arguments);// console.log([...arguments][0]) } getlist(11, 2, 3, 4); // 使用reduce方法實現(xiàn)forEach、map、filter const arr1 = [12, 21, 3]; const arr2 = arr1.map(function(item) {// console.log(this, item)return item*2 }, { msg: 'mapping' }) // console.log(arr1, arr2) // github上的 Array.prototype.selfMap = function () {const ary = thisconst result = []const [ fn, thisArg ] = [].slice.call(arguments)if (typeof fn !== 'function') {throw new TypeError(fn + 'is not a function') }for (let i = 0; i < ary.length; i++) {result.push(fn.call(thisArg, ary[i], i, ary))}return result }Array.prototype.reduceMap = function (fn, thisArg) {// return (list) => {// 不怎么愿意寫下面這兩個判斷條件const list = thisif (typeof fn !== 'function') {throw new TypeError(fn + 'is not a function') }if (!Array.isArray(list)) {throw new TypeError('list must be a Array')}if (list.length === 0) return []return list.reduce((acc, value, index) => {return acc.concat([ fn.call(thisArg, value, index, list) ])}, [])// } } // mine Array.prototype.imitateMap = function () {const list = this;const result = []const [fn, thisArg] = [].slice.call(arguments)if (typeof fn !== 'function') {throw new TypeError(fn + 'is not a function');}for (let i = 0; i < list.length; i++) {result.push(fn.call(thisArg, list[i], i, list));}return result; }Array.prototype.imitateReduceMap = function () {const list = this;const result = []const [fn, thisArg] = [].slice.call(arguments)if (typeof fn !== 'function') {throw new TypeError(fn + 'is not a function');}if (!Array.isArray(list)) {throw new TypeError(list + 'is not a Array');}return list.reduce((acc, curValue, index) => {return acc.concat([fn.call(thisArg, curValue, index, list)]);}, []) } const imitateReduceMap1 = function (fn, thisArg) {return (list) => {const result = []if (typeof fn !== 'function') {throw new TypeError(fn + 'is not a function');}if (!Array.isArray(list)) {throw new TypeError(list + 'is not a Array');}return list.reduce((acc, curValue, index) => {return acc.concat([fn.call(thisArg, curValue, index, list)]);}, [])} }console.log('imitateMap', arr1, arr1.imitateMap(function(item) {console.log('imitateMap this', this)return item + 1 }, { msg: 'mapping' }) ) console.log('imitateReduceMap', [ 1, 2, 3 ].imitateReduceMap(x => x + 1)); console.log('imitateReduceMap1', imitateReduceMap1(x => x + 1)([ 1, 2, 3 ])); /*** 實現(xiàn)repeat方法*/ function repeat(func, times, wait) {return (str) => {let count = 0;const timer = setInterval(() => {if (count < times) {// func.call(this, str);count++;} else {clearInterval(timer);}}, wait);} }const repeatFunc = repeat(alert, 3, 2000)repeatFunc('helloworld'); /*** 實現(xiàn)一個簡單的雙向綁定* 1.發(fā)布-訂閱模式* 2.臟值檢測* 3.數(shù)據(jù)劫持* Vue.js 采用的是 數(shù)據(jù)劫持+發(fā)布/訂閱模式 的方式，通過 Object.defineProperty() 來劫持各個屬性的 setter/getter， 在數(shù)據(jù)變動時發(fā)布消息給訂閱者（Wacther）, 觸發(fā)相應的監(jiān)聽回調(diào)*/ // 基于Object.defineProperty 實現(xiàn)數(shù)據(jù)劫持，利用了對Vue.js實現(xiàn)雙向綁定的思想 const obj = {} Object.defineProperty(obj, 'txt',{get:function(){return obj},set:function(newValue){document.getElementById('txt').value = newValuedocument.getElementById('show-txt').innerHTML = newValue} }) document.addEventListener('keyup', function(e){obj.txt = e.target.value })

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