javascript - 使用 JS 的数组映射 - 将值与另一个数组进行比较并从第二个数组返回值

Question

我想将此表的 chapter_id 和 brother_id 与下面的兄弟和章节表进行映射，并返回 brothername 和 name 字段分别。使用js或jquery。我正在使用 vuejs 返回分钟数组作为计算属性。见下文。

在sql中，它类似于

select brothername from brothers where minute.brother_id = brothers.id ... and then set the brothername as the new value for brother_id

chapter_id 也是如此:

select brothername from brothers where minute.brother_id = brothers.id ... and then set the brothername as the new value for brother_id

生成的数组或对象应该是:

预期数组

[
   {
      "location":"UCLA",
      "chapter_id":"Beta", 
      "brother_id":"Golpher", 
      "created_at":"2008-05-15 22:23:00",
      "status":"Approved"
   },
   { ... },
   {
      "location":"John's Deli",
      "chapter_id":"Beta", notice the change in the array based on the ids
      "brother_id":"Sheera", notice the change in the array based on the ids
      "created_at":"2008-05-15 22:23:00",
      "status":"Approved"
   }
]

分钟表(原始数组)

[
   {
      "location":"UCLA",
      "chapter_id":2,
      "brother_id":1,
      "created_at":"2008-05-15 22:23:00",
      "status":"Approved"
   },
   { ... },
   {
      "location":"John's Deli",
      "chapter_id":2,
      "brother_id":4,
      "created_at":"2008-05-15 22:23:00",
      "status":"Approved"
   }
]

章节表

[
   {
      "id":1,
      "letter_representation":"A",
      "name":"Alpha",
      "founded_at":"UCLA",
      ...
   },
   { ... }
]

兄弟的 table

[
   {
      "id":1,
      "profile_id":1,
      "chapter_id":1,
      "brothername":"Golpher",
      "firstname":"Jack",
      ...
   },
   { ... },
   {
      "id":4,
      "profile_id":4,
      "chapter_id":1,
      "brothername":"Sheera",
      "firstname":"Jake",
      ...
   }
]

Vue.js

computed: {
    brothers () {
        return this.$store.state.brothers
    },
    chapters () {
        return this.$store.state.chapters
    },
    minutes () {
        return this.$store.getters.model
    }
},

Answer 1

我假设您不想通过此操作改变原始数组中的对象。

注意您可能需要处理相应表中不存在brother_id或chapter_id的情况。在下面的示例中，它只是将属性值设置为 undefined

const minutesTable = [{
  "location": "UCLA",
  "chapter_id": 2,
  "brother_id": 1,
  "created_at": "2008-05-15 22:23:00",
  "status": "Approved"
}, {
  "location": "John's Deli",
  "chapter_id": 2,
  "brother_id": 4,
  "created_at": "2008-05-15 22:23:00",
  "status": "Approved"
}]
const chapterTable = [{
  "id": 1,
  "letter_representation": "A",
  "name": "Alpha",
  "founded_at": "UCLA",
}]
const brotherTable = [{
  "id": 1,
  "profile_id": 1,
  "chapter_id": 1,
  "brothername": "Golpher",
  "firstname": "Jack",
}, {
  "id": 4,
  "profile_id": 4,
  "chapter_id": 1,
  "brothername": "Sheera",
  "firstname": "Jake",
}]

// your result
const result = minutesTable.map(m => {
  const brother = brotherTable.find(b => b.id === m.brother_id)
  const chapter = chapterTable.find(c => c.id === m.chapter_id)

  return Object.assign({}, m, {
    brother_id: brother && brother.brothername,
    chapter_id: chapter && chapter.name,
  })
})

console.log(result)