精心收集的95個(gè)超實(shí)用的JavaScript代碼片段（ES6 +編寫(xiě)）
Array 數(shù)組
Array concatenation (數(shù)組拼接)
const ArrayConcat = （arr ，... args ）=> []。concat （arr ，... args ）;// ArrayConcat（[1 ,, [1,2,3，[4]]）-> [1,2,3，[4]]
Array difference (數(shù)組比較)
const difference = (a, b) => { const s = new Set(b); return a.filter(x => !s.has(x)); };// difference([1,2,3], [1,2]) -> [3]
Array includes (數(shù)組包含)
const includes = (collection, val, fromIndex=0) => collection.slice(fromIndex).indexOf(val) != -1;// includes("30-seconds-of-code", "code") -> true// includes([1, 2, 3, 4], [1, 2], 1) -> false
Array intersection (數(shù)組交集)
const intersection = (a, b) => { const s = new Set(b); return a.filter(x => s.has(x)); };// intersection([1,2,3], [4,3,2]) -> [2,3]
Array remove (移除數(shù)組中的元素)
const remove = (arr, func) =>Array.isArray(arr) ? arr.filter(func).reduce((acc, val) => {arr.splice(arr.indexOf(val), 1); return acc.concat(val);}, []): [];//remove([1, 2, 3, 4], n => n % 2 == 0) -> [2, 4]
Array sample (數(shù)組取樣隨，機(jī)獲取數(shù)組中的1個(gè)元素)
const sample = arr => arr[Math.floor(Math.random() * arr.length)];// sample([3, 7, 9, 11]) -> 9
Array union (數(shù)組合集)
const union = (a, b) => Array.from(new Set([...a, ...b]));// union([1,2,3], [4,3,2]) -> [1,2,3,4]
Array without (從數(shù)組中排除給定值)
const without = (arr, ...args) => arr.filter(v => args.indexOf(v) === -1);// without([2, 1, 2, 3], 1, 2) -> [3]// without([2, 1, 2, 3, 4, 5, 5, 5, 3, 2, 7, 7], 3, 1, 5, 2) -> [ 4, 7, 7 ]
Array zip (創(chuàng)建一個(gè)分組元素?cái)?shù)組)
const zip = (...arrays) => {const maxLength = Math.max.apply(null, arrays.map(a => a.length));return Array.from({length: maxLength}).map((_, i) => {return Array.from({length: arrays.length}, (_, k) => arrays[k][i]);})}//zip(['a', 'b'], [1, 2], [true, false]); -> [['a', 1, true], ['b', 2, false]]//zip(['a'], [1, 2], [true, false]); -> [['a', 1, true], [undefined, 2, false]]
Average of array of numbers (求數(shù)字?jǐn)?shù)組的平均數(shù))
const average = arr => arr.reduce((acc, val) => acc + val, 0) / arr.length;// average([1,2,3]) -> 2
Chunk array (數(shù)組分塊)
const chunk = (arr, size) =>Array.from({length: Math.ceil(arr.length / size)}, (v, i) => arr.slice(i * size, i * size + size));// chunk([1,2,3,4,5], 2) -> [[1,2],[3,4],[5]]
Compact (過(guò)濾掉數(shù)組中所有假值元素)
const compact = (arr) => arr.filter(v => v);// compact([0, 1, false, 2, '', 3, 'a', 'e'*23, NaN, 's', 34]) -> [ 1, 2, 3, 'a', 's', 34 ]
Count occurrences of a value in array (計(jì)數(shù)數(shù)組中某個(gè)值的出現(xiàn)次數(shù))
const countOccurrences = (arr, value) => arr.reduce((a, v) => v === value ? a + 1 : a + 0, 0);// countOccurrences([1,1,2,1,2,3], 1) -> 3
Deep flatten array (深度平鋪數(shù)組)
const deepFlatten = arr => [].concat(...arr.map(v => Array.isArray(v) ? deepFlatten(v) : v));// deepFlatten([1,[2],[[3],4],5]) -> [1,2,3,4,5]
Drop elements in array (刪除數(shù)組中的元素)
const dropElements = (arr, func) => {while (arr.length > 0 && !func(arr[0])) arr.shift();return arr;};// dropElements([1, 2, 3, 4], n => n >= 3) -> [3,4]
Fill array (填充數(shù)組)
const fillArray = (arr, value, start = 0, end = arr.length) =>arr.map((v, i) => i >= start && i < end ? value : v);// fillArray([1,2,3,4],'8',1,3) -> [1,'8','8',4]
Filter out non-unique values in an array (過(guò)濾出數(shù)組中的非唯一值)
const filterNonUnique = arr => arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i));// filterNonUnique([1,2,2,3,4,4,5]) -> [1,3,5]
Flatten array up to depth (根據(jù)指定的 depth 平鋪數(shù)組)
const flattenDepth = (arr, depth = 1) =>depth != 1 ? arr.reduce((a, v) => a.concat(Array.isArray(v) ? flattenDepth(v, depth - 1) : v), []): arr.reduce((a, v) => a.concat(v), []);// flattenDepth([1,[2],[[[3],4],5]], 2) -> [1,2,[3],4,5]
Flatten array (平鋪數(shù)組)
const flatten = arr => arr.reduce((a, v) => a.concat(v), []);// flatten([1,[2],3,4]) -> [1,2,3,4]
Get max value from array (獲取數(shù)組中的最大值)
const arrayMax = arr => Math.max(...arr);// arrayMax([10, 1, 5]) -> 10
Get min value from array (獲取數(shù)組中的最小值)
const arrayMin = arr => Math.min(...arr);// arrayMin([10, 1, 5]) -> 1
Group by (數(shù)組分組)
const groupBy = (arr, func) =>arr.map(typeof func === 'function' ? func : val => val[func]).reduce((acc, val, i) => { acc[val] = (acc[val] || []).concat(arr[i]); return acc; }, {});// groupBy([6.1, 4.2, 6.3], Math.floor) -> {4: [4.2], 6: [6.1, 6.3]}// groupBy(['one', 'two', 'three'], 'length') -> {3: ['one', 'two'], 5: ['three']}
Head of list (獲取數(shù)組的第一個(gè)元素)
const head = arr => arr[0];// head([1,2,3]) -> 1
Initial of list (排除數(shù)組中最后一個(gè)元素)
const initial = arr => arr.slice(0, -1);// initial([1,2,3]) -> [1,2]
Initialize array with range (初始化特定范圍的數(shù)組)
您可以省略 start ，默認(rèn)值?0。
const initializeArrayRange = (end, start = 0) =>Array.apply(null, Array(end - start)).map((v, i) => i + start);// initializeArrayRange(5) -> [0,1,2,3,4]
Initialize array with values (初始化特定范圍和值的數(shù)組)
const initializeArray = (n, value = 0) => Array(n).fill(value);// initializeArray(5, 2) -> [2,2,2,2,2]
Last of list (獲取數(shù)組的最后一個(gè)元素)
const last = arr => arr.slice(-1)[0];// last([1,2,3]) -> 3
Median of array of numbers (獲取數(shù)字?jǐn)?shù)組的中值)
const median = arr => {const mid = Math.floor(arr.length / 2), nums = arr.sort((a, b) => a - b);return arr.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2;};// median([5,6,50,1,-5]) -> 5// median([0,10,-2,7]) -> 3.5
Nth element of array (獲取數(shù)組的第N個(gè)元素)
const nth = (arr, n=0) => (n>0? arr.slice(n,n+1) : arr.slice(n))[0];// nth(['a','b','c'],1) -> 'b'// nth(['a','b','b']-2) -> 'a'
Pick(提取)
const pick = (obj, arr) =>arr.reduce((acc, curr) => (curr in obj && (acc[curr] = obj[curr]), acc), {});// pick({ 'a': 1, 'b': '2', 'c': 3 }, ['a', 'c']) -> { 'a': 1, 'c': 3 }// pick(object, ['a', 'c'])['a'] -> 1
Shuffle array (隨機(jī)排列數(shù)組)
const shuffle = arr => arr.sort(() => Math.random() - 0.5);// shuffle([1,2,3]) -> [2,3,1]
Similarity between arrays (獲取數(shù)組交集)
const similarity = (arr, values) => arr.filter(v => values.includes(v));// similarity([1,2,3], [1,2,4]) -> [1,2]
Sum of array of numbers (數(shù)字?jǐn)?shù)組求和)
const sum = arr => arr.reduce((acc, val) => acc + val, 0);// sum([1,2,3,4]) -> 10
Tail of list (返回剔除第一個(gè)元素后的數(shù)組)
const tail = arr => arr.length > 1 ? arr.slice(1) : arr;// tail([1,2,3]) -> [2,3]// tail([1]) -> [1]
Take right(從一個(gè)給定的數(shù)組中創(chuàng)建一個(gè)后N個(gè)元素的數(shù)組)
const takeRight = (arr, n = 1) => arr.slice(arr.length - n, arr.length);// takeRight([1, 2, 3], 2) -> [ 2, 3 ]// takeRight([1, 2, 3]) -> [3]
Take(從一個(gè)給定的數(shù)組中創(chuàng)建一個(gè)前N個(gè)元素的數(shù)組)
const take = (arr, n = 1) => arr.slice(0, n);// take([1, 2, 3], 5) -> [1, 2, 3]// take([1, 2, 3], 0) -> []
Unique values of array (數(shù)組去重)
const unique = arr => [...new Set(arr)];// unique([1,2,2,3,4,4,5]) -> [1,2,3,4,5]
Browser 瀏覽器
Bottom visible (頁(yè)面的底部是否可見(jiàn))
const bottomVisible = _ =>document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight || document.documentElement.clientHeight;// bottomVisible() -> true
Current URL (獲取當(dāng)前頁(yè)面URL)
const currentUrl = _ => window.location.href;// currentUrl() -> 'https://google.com'
Element is visible in viewport (判斷元素是否在可視窗口可見(jiàn))
const elementIsVisibleInViewport = (el, partiallyVisible = false) => {const { top, left, bottom, right } = el.getBoundingClientRect();return partiallyVisible? ((top > 0 && top < innerHeight) || (bottom > 0 && bottom < innerHeight)) &&((left > 0 && left < innerWidth) || (right > 0 && right < innerWidth)): top >= 0 && left >= 0 && bottom < = innerHeight && right <= innerWidth;};// 舉個(gè)例子，有一個(gè) 100x100 可視窗口， 和一個(gè) 10x10px 元素定位在 {top: -1, left: 0, bottom: 9, right: 10}// elementIsVisibleInViewport(el) -> false (not fully visible)// elementIsVisibleInViewport(el, true) -> true (partially visible)
Get scroll position (獲取滾動(dòng)條位置)
const getScrollPos = (el = window) =>({x: (el.pageXOffset !== undefined) ? el.pageXOffset : el.scrollLeft,y: (el.pageYOffset !== undefined) ? el.pageYOffset : el.scrollTop});// getScrollPos() -> {x: 0, y: 200}
Redirect to URL (重定向到URL)
const redirect = (url, asLink = true) =>asLink ? window.location.href = url : window.location.replace(url);// redirect('https://google.com')
Scroll to top (回到頂部)
const scrollToTop = _ => {const c = document.documentElement.scrollTop || document.body.scrollTop;if (c > 0) {window.requestAnimationFrame(scrollToTop);window.scrollTo(0, c - c / 8);}};// scrollToTop()
Date 日期
Get days difference between dates (獲取兩個(gè)日期之間相差的天數(shù))
const getDaysDiffBetweenDates = (dateInitial, dateFinal) => (dateFinal - dateInitial) / (1000 * 3600 * 24);// getDaysDiffBetweenDates(new Date("2017-12-13"), new Date("2017-12-22")) -> 9
Function 函數(shù)
Chain asynchronous functions (鏈?zhǔn)秸{(diào)用異步函數(shù))
const chainAsync = fns => { let curr = 0; const next = () => fns[curr++](next); next(); };/*chainAsync([next => { console.log('0 seconds'); setTimeout(next, 1000); },next => { console.log('1 second'); setTimeout(next, 1000); },next => { console.log('2 seconds'); }])*/
Curry (函數(shù)式編程術(shù)語(yǔ)：柯里化)
const curry = (fn, arity = fn.length, ...args) =>arity < = args.length? fn(...args): curry.bind(null, fn, arity, ...args);// curry(Math.pow)(2)(10) -> 1024// curry(Math.min, 3)(10)(50)(2) -> 2
Pipe (函數(shù)式編程術(shù)語(yǔ)：管道或?qū)Я?
const pipe = (...fns) => fns.reduce((f, g) => (...args) => g(f(...args)));/*const add5 = x => x + 5const multiply = (x, y) => x * yconst multiplyAndAdd5 = pipe(multiply, add5)multiplyAndAdd5(5, 2) -> 15*/
Promisify (柯里化一個(gè) Promise 函數(shù))
const promisify = func =>(...args) =>new Promise((resolve, reject) =>func(...args, (err, result) =>err ? reject(err) : resolve(result)));// const delay = promisify((d, cb) => setTimeout(cb, d))// delay(2000).then(() => console.log('Hi!')) -> Promise resolves after 2s
Run promises in series (運(yùn)行連續(xù)的 promises)
const series = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());// const delay = (d) => new Promise(r => setTimeout(r, d))// series([() => delay(1000), () => delay(2000)]) -> executes each promise sequentially, taking a total of 3 seconds to complete
Sleep (休眠)
const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));/*async function sleepyWork() {console.log('I\'m going to sleep for 1 second.');await sleep(1000);console.log('I woke up after 1 second.');}*/
Math 數(shù)學(xué)方法
Collatz algorithm(考拉茲算法)
const collatz = n => (n % 2 == 0) ? (n / 2) : (3 * n + 1);// collatz(8) --> 4// collatz(5) --> 16
Distance between two points (兩點(diǎn)之間的歐氏距離)
const distance = (x0, y0, x1, y1) => Math.hypot(x1 - x0, y1 - y0);// distance(1,1, 2,3) -> 2.23606797749979
Divisible by number (可以被某個(gè)數(shù)整除)
const isDivisible = (dividend, divisor) => dividend % divisor === 0;// isDivisible(6,3) -> true
Even or odd number (判斷奇偶數(shù))
const isEven = num => num % 2 === 0;// isEven(3) -> false
Factorial (階乘)
const factorial = n => n < = 1 ? 1 : n * factorial(n - 1);// factorial(6) -> 720
Fibonacci array generator (斐波納契數(shù)組發(fā)生器)
const fibonacci = n =>Array(n).fill(0).reduce((acc, val, i) => acc.concat(i > 1 ? acc[i - 1] + acc[i - 2] : i), []);// fibonacci(5) -> [0,1,1,2,3]
Greatest common divisor (GCD) (最大公約數(shù))
const gcd = (x, y) => !y ? x : gcd(y, x % y);// gcd (8, 36) -> 4
Hamming distance (漢明距離)
const hammingDistance = (num1, num2) =>((num1 ^ num2).toString(2).match(/1/g) || '').length;// hammingDistance(2,3) -> 1
Percentile (百分比)
const percentile = (arr, val) =>100 * arr.reduce((acc,v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0) / arr.length;// percentile([1,2,3,4,5,6,7,8,9,10], 6) -> 55
Powerset (冪集)
const powerset = arr =>arr.reduce((a, v) => a.concat(a.map(r => [v].concat(r))), [[]]);// powerset([1,2]) -> [[], [1], [2], [2,1]]
Round number to n digits (精確的幾位小數(shù))
const round = (n, decimals=0) => Number(`${Math.round(`${n}e${decimals}`)}e-${decimals}`);// round(1.005, 2) -> 1.01
Standard deviation (標(biāo)準(zhǔn)偏差)
const standardDeviation = (arr, usePopulation = false) => {const mean = arr.reduce((acc, val) => acc + val, 0) / arr.length;return Math.sqrt(arr.reduce((acc, val) => acc.concat(Math.pow(val - mean, 2)), []).reduce((acc, val) => acc + val, 0) / (arr.length - (usePopulation ? 0 : 1)));};// standardDeviation([10,2,38,23,38,23,21]) -> 13.284434142114991 (sample)// standardDeviation([10,2,38,23,38,23,21], true) -> 12.29899614287479 (population)
Media 媒體
Speech synthesis (語(yǔ)音合成，實(shí)驗(yàn)階段)
const speak = message => {const msg = new SpeechSynthesisUtterance(message);msg.voice = window.speechSynthesis.getVoices()[0];window.speechSynthesis.speak(msg);};// speak('Hello, World') -> plays the message
Node
Write JSON to file (將 JSON 寫(xiě)到文件)
const fs = require('fs');const jsonToFile = (obj, filename) => fs.writeFile(`${filename}.json`, JSON.stringify(obj, null, 2))// jsonToFile({test: "is passed"}, 'testJsonFile') -> writes the object to 'testJsonFile.json'
Object 對(duì)象
Object from key-value pairs (根據(jù)鍵值對(duì)創(chuàng)建對(duì)象)
const objectFromPairs = arr => arr.reduce((a, v) => (a[v[0]] = v[1], a), {});// objectFromPairs([['a',1],['b',2]]) -> {a: 1, b: 2}
Object to key-value pairs (對(duì)象轉(zhuǎn)化為鍵值對(duì) )
const objectToPairs = obj => Object.keys(obj).map(k => [k, obj[k]]);// objectToPairs({a: 1, b: 2}) -> [['a',1],['b',2]])
Shallow clone object (淺克隆對(duì)象)
const shallowClone = obj => Object.assign({}, obj);/*const a = { x: true, y: 1 };const b = shallowClone(a);a === b -> false*/
String 字符串
Anagrams of string (with duplicates) (字符串的排列組合，帶有重復(fù)項(xiàng))
const anagrams = str => {if (str.length < = 2) return str.length === 2 ? [str, str[1] + str[0]] : [str];return str.split('').reduce((acc, letter, i) =>acc.concat(anagrams(str.slice(0, i) + str.slice(i + 1)).map(val => letter + val)), []);};// anagrams('abc') -> ['abc','acb','bac','bca','cab','cba']
Capitalize first letter of every word (大寫(xiě)每個(gè)單詞的首字母)
const capitalizeEveryWord = str => str.replace(/\b[a-z]/g, char => char.toUpperCase());// capitalizeEveryWord('hello world!') -> 'Hello World!'
Capitalize first letter (首字母大寫(xiě))
const capitalize = ([first,...rest], lowerRest = false) =>first.toUpperCase() + (lowerRest ? rest.join('').toLowerCase() : rest.join(''));// capitalize('myName') -> 'MyName'// capitalize('myName', true) -> 'Myname'
Check for palindrome (檢查回文)
const palindrome = str => {const s = str.toLowerCase().replace(/[\W_]/g,'');return s === s.split('').reverse().join('');}// palindrome('taco cat') -> true
Reverse a string (反轉(zhuǎn)一個(gè)字符串)
const reverseString = str => [...str].reverse().join('');// reverseString('foobar') -> 'raboof'
Sort characters in string (alphabetical) (按字母順序排列字符串)
const sortCharactersInString = str =>str.split('').sort((a, b) => a.localeCompare(b)).join('');// sortCharactersInString('cabbage') -> 'aabbceg'
Truncate a String (截?cái)嘁粋€(gè)字符串)
const truncate = (str, num) =>str.length > num ? str.slice(0, num > 3 ? num - 3 : num) + '...' : str;// truncate('boomerang', 7) -> 'boom...'
Utility 實(shí)用函數(shù)
Escape regular expression (轉(zhuǎn)義正則表達(dá)式)
const escapeRegExp = str => str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');// escapeRegExp('(test)') -> \\(test\\)
Get native type of value (獲取原生類型的值)
const getType = v =>v === undefined ? 'undefined' : v === null ? 'null' : v.constructor.name.toLowerCase();// getType(new Set([1,2,3])) -> "set"
Hexcode to RGB (Hex轉(zhuǎn)RGB)
const hexToRgb = hex => `rgb(${hex.slice(1).match(/.{2}/g).map(x => parseInt(x, 16)).join()})`// hexToRgb('#27ae60') -> 'rgb(39,174,96)'
Is array(是否為數(shù)組)
const isArray = val => !!val && Array.isArray(val);// isArray(null) -> false// isArray([1]) -> true
Is boolean(是否為布爾值)
const isBoolean = val => typeof val === 'boolean';// isBoolean(null) -> false// isBoolean(false) -> true
Is function(是否為函數(shù))
const isFunction = val => val && typeof val === 'function';// isFunction('x') -> false// isFunction(x => x) -> true
Is number(是否為數(shù)字)
const isNumber = val => typeof val === 'number';// isNumber('1') -> false// isNumber(1) -> true
Is string(是否為字符串)
const isString = val => typeof val === 'string';// isString(10) -> false// isString('10') -> true
Is symbol(是否為symbol)
const isSymbol = val => typeof val === 'symbol';// isSymbol('x') -> false// isSymbol(Symbol('x')) -> true
Measure time taken by function (計(jì)算函數(shù)執(zhí)行所花費(fèi)的時(shí)間)
const timeTaken = callback => {console.time('timeTaken');const r = callback();console.timeEnd('timeTaken');return r;};// timeTaken(() => Math.pow(2, 10)) -> 1024// (logged): timeTaken: 0.02099609375ms
Number to array of digits (將數(shù)字轉(zhuǎn)化為整數(shù)數(shù)組)
const digitize = n => (''+n).split('').map(i => parseInt(i));// digitize(2334) -> [2, 3, 3, 4]
Ordinal suffix of number (數(shù)字序號(hào)的后綴)
const toOrdinalSuffix = num => {const int = parseInt(num), digits = [(int % 10), (int % 100)],ordinals = ['st', 'nd', 'rd', 'th'], oPattern = [1, 2, 3, 4],tPattern = [11, 12, 13, 14, 15, 16, 17, 18, 19];return oPattern.includes(digits[0]) && !tPattern.includes(digits[1]) ? int + ordinals[digits[0] - 1] : int + ordinals[3];};// toOrdinalSuffix("123") -> "123rd"
Random integer in range (在指定的范圍內(nèi)生成一個(gè)隨機(jī)整數(shù))
const randomIntegerInRange = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;// randomIntegerInRange(0, 5) -> 2
Random number in range (在指定的范圍內(nèi)生成一個(gè)隨機(jī)數(shù))
const randomInRange = (min, max) => Math.random() * (max - min) + min;// randomInRange(2,10) -> 6.0211363285087005
RGB to hexadecimal(RGB轉(zhuǎn)hex)
const rgbToHex = (r, g, b) => ((r << 16) + (g << 8) + b).toString(16).padStart(6, '0');// rgbToHex(255, 165, 1) -> 'ffa501'
Swap values of two variables (交換兩個(gè)變量的值)
[varA, varB] = [varB, varA];// [x, y] = [y, x]
URL parameters(網(wǎng)址參數(shù))
const getUrlParameters = url =>url.match(/([^?=&]+)(=([^&]*))/g).reduce((a, v) => (a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1), a), {});// getUrlParameters('http://url.com/page?name=Adam&surname=Smith') -> {name: 'Adam', surname: 'Smith'}
UUID generator (UUID生成器)
const uuid = _ =>([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c =>(c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16));// uuid() -> '7982fcfe-5721-4632-bede-6000885be57d'
Validate email(郵箱驗(yàn)證)
const validateEmail = str =>/^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/.test(str);// validateEmail([email protected]) -> true
Validate number (數(shù)字驗(yàn)證)
const validateNumber = n => !isNaN(parseFloat(n)) && isFinite(n) && Number(n) == n;// validateNumber('10') -> true
Value or default (值或者默認(rèn)值)
const valueOrDefault = (value, d) => value || d;// valueOrDefault(NaN, 30) -> 30
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