JavaScript如何将开发者薪资提取为单一数组？

方法1：使用filter() + map()（推荐） #

先通过filter()筛选出所有职位为developer的员工，再用map()提取每个员工的salary字段，直接得到单一数组：

const people = [
    {name: "bob", age: 20, position: "developer", salary: 120_000},
    {name: "susy", age: 26, position: "designer", salary: 140_000},
    {name: "peter", age: 33, position: "developer", salary: 220_000},
    {name: "cody", age: 51, position: "boss", salary: 400_000},
    {name: "franklin", age: 22, position: "designer", salary: 150_000},
    {name: "anna", age: 27, position: "developer", salary: 175_000},
    {name: "justin", age: 35, position: "developer", salary: 230_000},
    {name: "charlie", age: 23, position: "designer", salary: 120_000},
    {name: "tony", age: 38, position: "designer", salary: 210_000},
    {name: "ruth", age: 41, position: "developer", salary: 300_000}
];

function getDeveloperSalaries(array) {
    return array.filter(person => person.position === "developer")
                .map(developer => developer.salary);
}

const developerSalaries = getDeveloperSalaries(people);
console.log(developerSalaries); // 输出: [120000, 220000, 175000, 230000, 300000]

方法2：修改你的循环代码 #

你之前的问题是每次循环都创建了新数组，只要提前初始化一个空数组，把每个薪资push进去就能得到单一数组：

function getDeveloperSalaries(array) {
    const developers = array.filter(person => person.position === "developer");
    const salaries = []; // 初始化空数组
    for (let i = 0; i < developers.length; i++) {
        salaries.push(developers[i].salary); // 将薪资添加到数组中
    }
    return salaries;
}

const developerSalaries = getDeveloperSalaries(people);
console.log(developerSalaries); // 输出: [120000, 220000, 175000, 230000, 300000]

方法3：使用reduce()一步完成 #

reduce()可以同时完成筛选和提取，适合想简化代码的场景：

function getDeveloperSalaries(array) {
    return array.reduce((salaries, person) => {
        if (person.position === "developer") {
            salaries.push(person.salary);
        }
        return salaries;
    }, []); // 初始值为空数组
}

const developerSalaries = getDeveloperSalaries(people);
console.log(developerSalaries); // 输出: [120000, 220000, 175000, 230000, 300000]

内容的提问来源于stack exchange，提问作者kewl