超级合并在那里?(超级合并单元格)
555
2022-05-29
1、展开操作符
let firstHalf = [ one , two ];let secondHalf = [ three , four , ...firstHalf];
let firstHalf = [ one , two ];let secondHalf = [ three , four ];for(var i=0, i const hero = { name: Xena - Warrior Princess , realName: Lucy Lawless}const heroWithSword = { ...hero, weapon: sword} let keys = Object.keys(hero); let obj = {}; for(var i=0; i< keys.length; i++) { obj[keys[i]] = keys[props[i]]; } 2、剩余参数 function add(first, second, ...remaining) { return first + second;} function add(first, second, ...remaining) { return first + second + remaining.reduce((acc, curr) => acc + curr, 0);} 3、字符串插值 class Product { constructor(name, description, price) { this.name = name; this.description = description; this.price = price; }getDescription() { return " Full description" + " name: " + this.name + " description: " + this.description }} getDescription() { return `Full description: name: ${this.name} description ${this.description} `;} 4、简写属性 function createCoord(x, y) { return { x: x, y: y }} function createCoord(x, y) { return { x, y }} 5、方法属性 const math = { add: function(a,b) { return a + b; }, sub: function(a,b) { return a - b; }, multiply: function(a,b) { return a * b; }} const math = { add(a,b) { return a + b; }, sub(a,b) { return a - b; }, multiply(a,b) { return a * b; }} 6、解构赋值 function handle(req, res) { const name = req.body.name; const description = req.body.description; const url = req.url; log( url endpoint , url); // 大量代码逻辑 dbService.createPerson(name, description) } function handle(req, res) { const { body: { name, description }, url } = req; log( url endpoint , url); // 大量代码逻辑 dbService.createPerson(name, description) const array = [1,2,3,4,5,6];const a = array[0];const c = array[2]; const array = [1,2,3,4,5,6]; const [a, ,c, ...remaining] = arr; // remaining = [4,5,6] function doSomething(config) { if(config.a) { ... } if(config.b) { ... } if(config.c) { ... }} function doSomething({ a, b, c }) { if(a) { ... } if(b) { ... } if(c) { ... }} 7、数组方法 find(),查找列表中的成员,返回 null 表示没找到 findIndex(),查找列表成员的索引 some(),检查某个断言是否至少在列表的一个成员上为真 includes,列表是否包含某项 const array = [{ id: 1, checked: true }, { id: 2 }]; arr.find(item => item.id === 2) // { id: 2 } arr.findIndex(item => item.id === 2) // 1 arr.some(item => item.checked) // true const numberArray = [1,2,3,4]; numberArray.includes(2) // true Promises + Async/Await 8、异步方案 function doSomething(cb) { setTimeout(() => { cb( done ) }, 3000) } doSomething((arg) => { console.log( done here , arg); }) function doSomething() { return new Promise((resolve, reject) => { setTimeout(() => { resolve( done ) }, 3000) }) } doSomething().then(arg => { console.log( done here , arg); }) getUser() .then(getOrderByUser) .then(getOrderItemsByOrder) .then(orderItems => { // 处理排序后的成员 }) async function getItems() { try { const user = await getUser(); const order = await getOrderByUser(user); const items = await getOrderItemsByOrder(order); return items; } catch(err) { // 在这里处理错误,建议返回某个值或者重新抛出错误 } } getItems().then(items => { // 处理排序后的成员 } 9、模块 // math.js export function add(a,b) { return a + b; } export function sub(a,b) { return a - b; } export default mult(a,b) => a * b; // main.js import mult, { add, sub } from ./math ; mult(2, 4) // 8 add(1,1) // 2 sub(1,2) // -1 软件开发
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