如何字符串化循环 JSON 对象并将其保存到文件？

Question

I'm working on a radial tree diagram in javascript using d3.js and jquery. I use json files to load data into a javascript var. After working on a diagram and making some changes, eg changing parent of some nodes, I want to stringify data and save as a json file. When I stringify treeData variable, which includes all json data, and wanted to display it, I receive only the root node stringified. This is my code:

var json = JSON.stringify(treeData.children, function(key,value){
    if(key == "children"){
        return undefined;
    }
    return value;
});
alert("Json: " + json);

Also I don't know why the key is set to "children". My JSON file structure:

{
 "name": "root",
 "children": [
  {
   "name": "child1",
   "children": [ ... ]
  }
 ]
}

Answer 1

您的对象文字中有一个children键，因此它被传递给回调，然后由于某种原因您返回 undefined，这将从结果中删除该键。

Answer 2

Circular JSON Objects can be stringified and saved with the following approach:

import stringify from 'json-stringify-safe';
import fs from 'fs';

const content = stringify(myCircularJSONObject);

fs.writeFile('./data.json', content, ()=>{console.log('CREATED')});

Answer 3

If I understand correctly you are trying to achieve stringifying of an object structured as:

var obj = {};
obj.circle = obj;
var str = JSON.stringify(obj);
// → Error

This object will return an error with JSON.stringify although is otherwise valid. If you don't mind the readability of the stringified object, I suggest using CircularJSON :

Install when using Node.js:

npm install --save circular-json

Install for web:

<script src="build/circular-json.js"></script>

And usage:

var object = {};
object.arr = [
    object, object
];
object.arr.push(object.arr);
object.obj = object;

var serialized = CircularJSON.stringify(object);
// → '{"arr":["~","~","~arr"],"obj":"~"}'

var unserialized = CircularJSON.parse(serialized);
// → { arr: [ [Circular], [Circular] ], obj: [Circular] }

Answer 4

The problem is that using tree data will return with a loop and circular data error. Switching key from "children" to "parent" give a json without references to the parents and work properly.