Javascript |从对象数组中删除不需要的数据

Question

我只想要数组对象中的第一年和去年元素

例如，这是数据(它已排序，所以我只是不想搞乱):

[
  { make: 'audi', model: 'rs5', year: '2013' },
  { make: 'audi', model: 'rs5', year: '2015' },
  { make: 'audi', model: 'r8', year: '2020' },
  { make: 'ford', model: 'mustang', year: '2012' },
  { make: 'ford', model: 'fusion', year: '2015' },
  { make: 'ford', model: 'mustang', year: '2033' },
  { make: 'kia', model: 'optima', year: '2010' },
  { make: 'kia', model: 'optima', year: '2012' },
  { make: 'kia', model: 'optima', year: '2020' },
  { make: 'kia', model: 'optima', year: '2030' },
  { make: 'kia', model: 'optima', year: '2040' }
]

我希望像这样删除所有的中年:

[
  { make: 'audi', model: 'rs5', year: '2013' },
  { make: 'audi', model: 'r8', year: '2020' },
  { make: 'ford', model: 'mustang', year: '2012' },
  { make: 'ford', model: 'mustang', year: '2033' },
  { make: 'kia', model: 'optima', year: '2010' },
  { make: 'kia', model: 'optima', year: '2040' }
]

Answer 1

您可以通过 make 分隔数组，然后获取每个 make 的第一个和最后一个值:

const arr = [
  { make: 'audi', model: 'rs5', year: '2013' },
  { make: 'audi', model: 'rs5', year: '2015' },
  { make: 'audi', model: 'r8', year: '2020' },
  { make: 'ford', model: 'mustang', year: '2012' },
  { make: 'ford', model: 'fusion', year: '2015' },
  { make: 'ford', model: 'mustang', year: '2033' },
  { make: 'kia', model: 'optima', year: '2010' },
  { make: 'kia', model: 'optima', year: '2012' },
  { make: 'kia', model: 'optima', year: '2020' },
  { make: 'kia', model: 'optima', year: '2030' },
  { make: 'kia', model: 'optima', year: '2040' }
]

const grouped = arr.reduce((a, el) => (a[el.make] ? a[el.make].push(el) : a[el.make] = [el], a), {})
const out = Object.values(grouped).reduce((a, group) => (a.push(group[0], group[group.length - 1]), a), [])

console.log(out)