javascript - 有条件地创建数组(Javascript)

Question

我们如何从数组中提取特定字段的值(我想提取id值)

[
    {id:1, added: true, name: 'Book'}, -> I want to extract id value!
    {id:2, added: true, name: 'Desk'},
    {id:5, added: true, name: 'Rock'},
    {id:3, added: false, name: 'Rock'},
    {id:7, added: false, name: 'Rock'},
    {id:8, added: false, name: 'Rock'},
]

并使用值创建一个数组。 (仅当添加的字段为 true)

预期输出将为[1, 2, 5]。

如果我们能够在获取 [] 空数组时捕获边缘情况，那就太好了。

请随意使用 lodash(如果它比 vanila javascript 更快、更简单)

Answer 1

您只需使用 Array#filter与 Array#map 结合功能

const arr = [
    {id:1, added: true, name: 'Book'},
    {id:2, added: true, name: 'Desk'},
    {id:5, added: true, name: 'Rock'},
    {id:3, added: false, name: 'Rock'},
    {id:7, added: false, name: 'Rock'},
    {id:8, added: false, name: 'Rock'},
];

const mappedArr = arr.filter(item => item.added).map(item => item.id);

console.log(mappedArr);