how to update a deeply nested object in Javascript?-CodePudding

I have a this type of a json object.

 {
    "id": "001",
    "type": "A",
    "value": "aaaaa",
    "data:": {},
    "children": [
        {
            "id": "002",
            "type": "A",
            "value": "aaaaa",
            "data:": {},
            "children": []
        },
        {
            "id": "003",
            "type": "A",
            "value": "aaaaa",
            "data:": {},
            "children": [
                {
                    "id": "00001",
                    "type": "B",
                    "children": []
                }
            ]
        },
        {
            "id": "004",
            "type": "A",
            "value": "aaaaa",
            "data:": {},
            "children": [
                {
                    "id": "005",
                    "type": "A",
                    "value": "aaaaa",
                    "data:": {},
                    "children": []
                },{
                    "id": "005",
                    "type": "A",
                    "value": "aaaaa",
                    "data:": {},
                    "children": [
                        {
                            "id": "00002",
                            "type": "B",
                            "children": []
                        }
                    ]
                }
            ]
        },
        {
            "id": "00003",
            "type": "B",
            "children": []
        }
    ]
}

I need to replace all the object which is type: "B" , with this (which is mentioned below) type of object which I can get from an object with ids as keys of typed B. This typed B objects can be nested anywhere either as a first child or fifth child of a nested arrays of children

{
    "id": "002",
    "type": "A",
    "value": "aaaaa",
    "data:": {},
    "children": []
},

How can I do that? This can be deeply nested and there's no specific place where we should replace the objects, beforehand. So, I need to go through the entire object and do that. How should I get it done ?

CodePudding user response：

I played around with this in the console and it did what you wanted (based on the json array provided, setting all the "B" to "A" types). It's a recursive function so on any nested child it meets in the "children" array it would call the function again on each item in the array.


function fixObjects (obj) {
  if (obj["type"] === "B") {
    obj["type"] = "A";
    obj["id"] = "002";
    obj["value"] = "aaaaa";
    obj["data"] = {};
  } 
  if (obj["children"].length > 0) {
     obj["children"].forEach (child => fixObjects (child));
  }
}

fixObjects (_yourArray)

CodePudding user response：

This looks like a tree traversal problem. Here's a way to handle that with depth-first search without recursion.

const data = {"id":"001","type":"A","value":"aaaaa","data:":{},"children":[{"id":"002","type":"A","value":"aaaaa","data:":{},"children":[]},{"id":"003","type":"A","value":"aaaaa","data:":{},"children":[{"id":"00001","type":"B","children":[]}]},{"id":"004","type":"A","value":"aaaaa","data:":{},"children":[{"id":"005","type":"A","value":"aaaaa","data:":{},"children":[]},{"id":"005","type":"A","value":"aaaaa","data:":{},"children":[{"id":"00002","type":"B","children":[]}]}]},{"id":"00003","type":"B","children":[]}]};

const dfs = () => {
  const stack = [data];
  
  while(stack.length) {
    const curr = stack.pop();
    // check for match on type
    if (curr.type === "B") {
      curr.type = "A";
      curr.id = "002";
      curr.value = "aaaaa";
      curr.data = {};
    }
    curr.children.forEach(child => {
      stack.push(child);
    });
  }
};

dfs();

const output = document.getElementById("output");
output.innerText = JSON.stringify(data, null, 2);

<pre id="output" />

CodePudding user response：

You can use Array Filter to remove

const data = {"id":"001","type":"A","value":"aaaaa","data:":{},"children":[{"id":"002","type":"A","value":"aaaaa","data:":{},"children":[]},{"id":"003","type":"A","value":"aaaaa","data:":{},"children":[{"id":"00001","type":"B","children":[]}]},{"id":"004","type":"A","value":"aaaaa","data:":{},"children":[{"id":"005","type":"A","value":"aaaaa","data:":{},"children":[]},{"id":"005","type":"A","value":"aaaaa","data:":{},"children":[{"id":"00002","type":"B","children":[]}]}]},{"id":"00003","type":"B","children":[]}]};

const removeType = (data, type) => {
  if (data.type === type) {
    return null;
  }
  if (data.children) {
    data.children = data.children.filter((child) => removeType(child, type));
  }
  return data;
};

console.log(removeType(data, "B"));