function fetchMessages(username) { return fetch(`https://example.com/api/messages/${username}`) .then(response => response.json());}function getUsername(person) { return person.username;}function chainedFetchMessages(p, username) { // In this function, p is a promise. We wait for it ...
function fetchMessages(username) { return fetch(`https://example.com/api/messages/${username}`) .then(response => response.json()); } function getUsername(person) { return person.username; } async function chainedFetchMessages(p, username) { // In this function, p is a promise. We wait...
AI代码解释 functionkeyByUsernameReducer(acc,person){return{...acc,[person.username]:person};}constpeopleObj=peopleArr.reduce(keyByUsernameReducer,{});console.log(peopleObj);// ⦘ {// "glestrade": {// "username": "glestrade",// "displayname": "Inspector Lestrade",// "email": "glestra...
js reduce 高阶函数。 tcp udp function myReduce(arr,cb){ //简单模式,没有初值 let res = arr[0]; for(let i = 1 ;i<arr.length;i++){ const cur = arr[i]; res = cb(res,cur,i,arr); } return res; } https://zhuanlan.zhihu.com/p/24860273... ...
functionmyReducer(accumulator,arrayElement){ // Code to do something goes here } accumulator是一个叠加值。它包含上次调用 reducer 函数时返回的所有内容。如果 reducer 函数还没有被调用,那么它包含初始...
The reduce method executes a reducer function on each element of the array. This results in a single output value calculated from the elements. The reducer function takes four arguments: accumulator, current value, current index, and source array. The accumulator accumulates the callback's return...
MDN example 往往地 reduce语法 (method) Array<number>.reduce(callbackfn: (previousValue: number, currentValue: number, currentIndex: number, array: number[]) => number): number (+2 overloads) Calls the specified callback function for all the elements in an array. ...
}functiongetLastSeen(x) {returnx.lastSeen; }functiongreater(a, b) {return(a > b) ? a : b; }constpeopleWithEmail = peopleArr.filter(notEmptyEmail);constlastSeenDates = peopleWithEmail.map(getLastSeen);constmostRecent = lastSeenDates.reduce(greater,'');console.log(mostRecent);// ⦘...
reduce(function(accumulator, currentValue, currentIndex, array){ return accumulator + currentValue; });查看中间结果也是可以的[0, 1, 2, 3, 4].reduce(function (accumulator, currentValue, currentIndex, array) { stepRes = accumulator + currentValue console.log('accumulator,currentValue,currentIndex,...
Returns true if any of the elements in the array pass the test, otherwise it returns false JavaScript Version: 1.8More ExamplesExample Round all the number is an array, and display the sum: Try itSum of numbers in array: var numbers = [15.5, 2.3, 1.1, 4.7];function getSum(total, num...