JavaScript递归调用Axios.get [英] JavaScript Recursively call Axios.get

问题描述

我有一个API，该API返回具有多个记录的父子关系

I have an API that returns a Parent Child relationship with multiple records

第一次调用API http://someAPI/getResult/?parent = null会给我:

First call to API http://someAPI/getResult/?parent=null will give me:

{
   ParentID: null,
   Id: 1,
   Name: 'Top Level Element'
}

第二个调用应该是http://someAPI/getResult/?parent = 1，它将返回:

Second call should be to http://someAPI/getResult/?parent=1 and that will return:

[
  {
    ParentID: 1,
    ID: 2,
    Name:  'Second Level Element First Element'
  },
  {
    ParentID: 1,
    ID: 3,
    Name:  'Second Level Element Second Element'
  }
]

下一个应该是http://someAPI/getResult/?parent = 2，然后是http://someAPI/getResult/?parent = 3.那些人将返回自己的孩子，直到最终没有孩子返回.

The next should be http://someAPI/getResult/?parent=2 and then http://someAPI/getResult/?parent=3. Those will return their own children until finally no children are returned.

我如何编写一个递归函数，该函数将从顶层(ParentID = null)直到最后一个孩子(没有其他记录)检索所有条目?

How can I write a recursive function that will retrieve all entries from the top level (ParentID = null) until the last child (no further records)?

推荐答案

使用手动堆栈处理递归可能最简单.

It might be simplest to handle the recursion with a manual stack.

由于这是一个 async 函数，它将返回一个Promise，该Promise最终将解析为一个包含每个 parent = ...

As this is an async function, it will return a Promise that should eventually resolve to an object containing the responses for each parent=...

async function getTree() {
  const idsToCheck = ["null"];
  const results = {};
  while (idsToCheck.length) {
    const id = idsToCheck.shift();
    if (results[id]) {
      // We've already processed this node
      continue;
    }
    const resp = await fetch("http://someAPI/getResult/?parent=" + id);
    if (!resp.ok) throw new Error("response not ok");
    const data = await resp.json();
    results[id] = data;
    data.forEach((child) => {
      idsToCheck.push(child.Id);
    });
  }
  return results;
}

(另一种使用实际递归函数调用的公式:

(Another formulation that uses actual recursive function calls:

async function getTree() {
  const results = {};
  async function populateResults(id) {
    if (results[id]) {
      // We've already processed this node
      return;
    }
    const resp = await fetch("http://someAPI/getResult/?parent=" + id);
    if (!resp.ok) throw new Error("response not ok");
    const data = await resp.json();
    results[id] = data;
    for (let child of data) {
      await populateResults(results, child.Id);
    }
  }
  await populateResults("null");
  return results;
}

)

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