在lodash中使用topair展平嵌套对象

Question

我有一个这样的对象：

let order={
  "john":{
    "hamburger":4
  },
  "alice":{
    "pizza":10,
    "milkshake":2
  },
  "bob":{
  }
}

我想像这样扁平化：

let res=[
   ["john","hamburger",4],

   ["alice","pizza",4],
   ["alice","milkshake",4]

]

我知道如何使用keyBy反向操作，但如何将其从递归对象转换为递归数组？我试着使用toPairs，但我想不出如何使它递归

Answer 1

使用_.toPairs()获取[name, items]对的数组，并使用_.flatMap()对其进行迭代。从items对象获取对，并使用_.map()创建包含信息的数组：

​

const { flatMap, toPairs, map } = _

const order = {"john":{"hamburger":4},"alice":{"pizza":10,"milkshake":2},"bob":{}}

const result = flatMap(
  toPairs(order),
  ([name, items]) => 
    map(
      toPairs(items),
      ([product, price]) => [name, product, price]
    )
)

console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js" integrity="sha512-WFN04846sdKMIP5LKNphMaWzU7YpMyCU245etK3g/2ARYbPK9Ub18eG+ljU96qKRCWh+quCY7yefSmlkQw1ANQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

​

在vanilla JS中，您可以结合使用Array.flatMap()和Object.entries()来获得相同的结果：

​

const order = {"john":{"hamburger":4},"alice":{"pizza":10,"milkshake":2},"bob":{}}

const result = Object
  .entries(order)
  .flatMap(([name, items]) =>
    Object.entries(items)
      .map(([product, price]) => [name, product, price])
  )

console.log(result)

​