[英]Return array of objects (from array of objects)
我有以下数据,并且我想返回不同years
(对象)数组。
我尝试了以下功能,但在数组中获取了数组。
const data = [{ id: 1, name: "test1", years: [{ id: 1, name: "year1" }, { id: 2, name: "year2" }] }, { id: 2, name: "test2", years: [{ id: 1, name: "year1" }] }, ] let years = data.map((s) => { return s.years }) let distinctYears = Array.from(new Set(years.map(c => c.id))).map(id => { return { id: id, name: years.find(c => c.id === id).name, } }) console.log(distinctYears);
期望的结果:
[
{id: 1, name: "year1"},
{id: 2, name: "year2"}
]
由于s.years()
是一个数组,并且data.map()
返回结果的数组, years
必然是一个数组的数组。
而不是使用.map()
,而使用.reduce()
来连接它们。
const data = [{ id: 1, name: "test1", years: [{ id: 1, name: "year1" }, { id: 2, name: "year2" }] }, { id: 2, name: "test2", years: [{ id: 1, name: "year1" }] }, ]; const years = data.reduce((a, { years }) => a.concat(years), []); let distinctYears = Array.from(new Set(years.map(c => c.id))).map(id => { return { id: id, name: years.find(c => c.id === id).name, } }); console.log(distinctYears);
您可以通过多种方式进行此操作。 这是一个,不是一线,而是分解为多个部分,以帮助我们了解发生了什么。
您的数据集:
let data =
[
{
id: 1,
name: "test1",
years: [{id: 1, name: "year1"}, {id: 2, name: "year2"} ]
},
{
id: 2,
name: "test2",
years: [{id: 1, name: "year1"} ]
},
]
使用.flatMap()
创建一个包含所有项目的一级数组:
let allItems = data.flatMap((item) => {
return item.years.map((year) => {
return year
})
})
获取不同的项目:
let distinct = []
allItems.forEach((item) => {
let matchingItem = distinct.find((match) => match.id == item.id && match.name == item.name)
if(!matchingItem){
distinct.push(item)
}
})
在实践中:
let data = [{ id: 1, name: "test1", years: [{ id: 1, name: "year1" }, { id: 2, name: "year2" }] }, { id: 2, name: "test2", years: [{ id: 1, name: "year1" }] }, ] let allItems = data.flatMap((item) => { return item.years.map((year) => { return year }) }) let distinct = [] allItems.forEach((item) => { let matchingItem = distinct.find((match) => match.id == item.id && match.name == item.name) if (!matchingItem) { distinct.push(item) } }) console.log(distinct)
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