如何將一組對象轉換回一個 object

Question

我得到了一組具有以下結構的對象：

const cars = {
  ford: {
    entries: ['ford 150']
  },
  chrysler: {
    entries: ['Voyager']
  },
  honda: {
    entries: []
  },
  toyota: {
    entries: ['sienna']
  },
  mercedes: {
    entries: []
  },
}

為了讓用戶能夠重新排列汽車的順序，我需要過濾掉條目為零的汽車品牌，所以我這樣做：

const filteredCars = Object.values(cars).filter(removeCarsWithNoEntries)

function removeCarsWithNoEntries(e) {
  if (e.entries[0]) return e.entries
}

然后，一旦順序重新排列，我必須將 object 轉換回其原始形式，但順序重新排列，意思是這樣的：

cars = {
   toyota: {
    entries: ['sienna']
  },
  chrysler: {
    entries: ['Voyager']
  },
  ford: {
    entries: ['ford 150']
  },
  honda: {
    entries: []
  },
  mercedes: {
    entries: []
  },
}

我已經閱讀了array.reduce和Object.assign但到目前為止我嘗試過的東西不起作用。

如何將對象數組轉換回具有 0 個條目的原始汽車品牌的單個 object？ 謝謝。

Answer 1

You can convert the object to entries via Object.entries() , and then filter/sort by the value (the 2nd item in the pair), and convert back to an object using Object.fromEntries() :

 const cars = {"ford":{"entries":["ford 150"]},"chrysler":{"entries":["Voyager"]},"honda":{"entries":[]},"toyota":{"entries":["sienna"]},"mercedes":{"entries":[]}} const sorted = Object.fromEntries( Object.entries(cars).sort(([, { entries: a }], [, { entries: b }]) => b.length - a.length) ) const filtered = Object.fromEntries( Object.entries(cars).filter(([, v]) => v.entries.length) ) console.log({ sorted, filtered })

Answer 2

檢查您的代碼... filter方法不起作用，因為返回一個數組...您是否需要使用length屬性來檢查是否有值，否則它將始終為true

 const cars = { ford: { entries: ['ford 150'] }, chrysler: { entries: ['Voyager'] }, honda: { entries: [] }, toyota: { entries: ['sienna'] }, mercedes: { entries: [] }, } filtered = {} Object.keys(cars).forEach(removeCarsWithNoEntries) function removeCarsWithNoEntries(brand) { if(.cars[brand].entries.length) return filtered[brand] = cars[brand] } console.log(filtered)