異步發布父子物件和關系（遞回？）

假設我正在嘗試創建一個“家譜”作為一個 JSON 陣列。

所以我有一個Person物件陣列。

每個Person物件都有一個強制性的name. 每個物件還可以選擇有一個children包含其他Person物件陣列的欄位（也有一個children欄位 - 因此家譜的“深度”基本上可以永遠持續下去。）

如果沒有孩子，該children欄位將只是一個空陣列[]。

例如

  const family_name = "The Numbers";
  const family = [{
      name: "1"
      children: [],
    },
    {
      name: "2"
      children: [{
          name: "2 - 1",
          children: [],
        },
        {
          name: "2 - 2",
          children: [{
            name: "2 - 2 - 1",
            children: [],
          }, ],
        }
      ],
    },
    {
      name: "3"
      children: [{
        name: "3 - 1",
        children: [],
      }, ],
    },
  ]

我需要在“孩子”之前發布“父母”。當我 POST a 時Person，我會id在response.data. 這id需要在直接子項的 POST 中用作 a，parent_id以便子項與父項相關聯。

我還需要首先發布“family_name”，這將回傳一個family_id. 這family_id將僅用parent_id作最頂層的Persons。

例如

axios.post(FAMILY_URL, {"family_name": family_name})
    .then((response) => {
        // Promise.all() POST 1, 2, and 3 with their "parent_id" as response.data.family_id
        // Promise.all() POST 2-1 and 2-2 with their "parent_id" as 2's response.data.id
        // POST 2-2-1 with its "parent_id" as 2-1's response.data.id
        // POST 3-1 with its "parent_id" as 3's response.data.id
    })

但是如果Person物件的數量和深度未知，代碼會是什么樣子呢？我必須利用遞回函式，對嗎？

我還想對所有“兄弟姐妹”使用 Promise.all()

uj5u.com熱心網友回復：

你想遞回地遍歷資料結構，一路積累承諾

// fake axios, ignore this bit
const FAMILY_URL="family-url",axios={post:async(a,o)=>(console.log(`POST ${a}`,o),{data:{id:`${a===FAMILY_URL?"":`${o.parent_id}-`}${Math.ceil(100*Math.random())}`}})};

// resolves an individual person by posting their details with a given
// parent ID, then doing the same for any children
const savePerson = async (parent_id, { name, children }) => {
  // get this person's ID
  const { data: { id } } = await axios.post("person-url", {
    name,
    parent_id
  })
  
  return {
    id, // assign the ID for visibility
    name,
    // pass this person's ID as the children's parent
    children: await savePeople(id, children)
  }
}

// resolves an array of people given a "parent ID"
const savePeople = (parent_id, people) =>
  Promise.all(people.map(person => savePerson(parent_id, person)))

// Top-level family helper
const saveFamily = async (family_name, family) => {
  const { data: { id } } = await axios.post(FAMILY_URL, { family_name })
  
  // resolve all the people in the family array
  return savePeople(id, family)
}

// minified
const family = [{"name":"1","children":[]},{"name":"2","children":[{"name":"2 - 1","children":[]},{"name":"2 - 2","children":[{"name":"2 - 2 - 1","children":[]}]}]},{"name":"3","children":[{"name":"3 - 1","children":[]}]}]

saveFamily("Smith", family).then(console.info)

.as-console-wrapper { max-height: 100% !important; }

uj5u.com熱心網友回復：

我會使用 BFS 演算法來處理它。例子：

function postFamily(family) {

    const queue = [];
    queue.unshift(...family);

    while (queue.length) {
        const cur = queue.pop();

        // HERE IS YOUR LOGIC RELATED TO THE CURRENT NODE
        // FOR EXAMPLE:
        axios.post('*FAMILY URL*', cur);

        for (const child of cur) {
            queue.unshift(child);
        }
    }
}

我不清楚想要的結果，但如果它會有所幫助，我很高興。祝你今天過得愉快！

標籤：javascript 递归 公理

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