1：找出数组中总和，最大值，最小值

const array  = [5,4,7,8,9,2];console.log('总和', array.reduce((a, b) =>a+b)); //35console.log('最大值', array.reduce((a,b) => a>b?a:b)); //9console.log('最小值', array.reduce((a,b) => a<b?a:b)); //2

2: 对字符串，数字或对象数组进行排序

const stringArr = ["Joe", "Kapil", "Steve", "Musk"]console.log('排序1', stringArr.sort()); // ['Joe', 'Kapil', 'Musk', 'Steve']// 排序数字数组const array = [40, 100, 1, 5, 25, 10];console.log('排序数字数组', array.sort((a, b) => a - b));//[1, 5, 10, 25, 40, 100]//从大到小console.log('从大到小', array.sort((a,b) => b-a));//[100, 40, 25, 10, 5, 1]//对象数组排序const objectArr = [     { first_name: 'Lazslo', last_name: 'Jamf'     },    { first_name: 'Pig',    last_name: 'Bodine'   },    { first_name: 'Pirate', last_name: 'Prentice' }];objectArr.sort((a, b) => a.last_name.localeCompare(b.last_name));// 输入(3) [{…}, {…}, {…}]0: {first_name: "Pig", last_name: "Bodine"}1: {first_name: "Lazslo", last_name: "Jamf"}2: {first_name: "Pirate", last_name: "Prentice"}length: 3

3: 删除反复值

const array  = [5,4,7,8,9,2,7,5];array.filter((item,idx,arr) => arr.indexOf(item) === idx);// orconst nonUnique = [...new Set(array)];// 输入: [5, 4, 7, 8, 9, 2]

4：合并多个对象

const user = {            name: 'Kapil Raghuwanshi',            gender: 'Male'};const college = {            primary: 'Mani Primary School',            secondary: 'Lass Secondary School'};const skills = {            programming: 'Extreme',            swimming: 'Average',            sleeping: 'Pro'};const summary = {            ...user,            ...college,            ...skills};console.log('summar', summary);// 输入gender: "Male"name: "Kapil Raghuwanshi"primary: "Mani Primary School"programming: "Extreme"secondary: "Lass Secondary School"sleeping: "Pro"swimming: "Average"

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