Typescript classes deserialized json-CodePudding

I have 2 classes that represent a Tree structure as follows:

class Node {
        private _id: string;
        name: string;
        parent?: Node;
        children: Node[];
}

class Tree {
    root: Node;
    treeMap: Map<string, Node>;
}

I am writing a api GET /tree which should return tree json in the following manner:

[
    {
        "1": {
            "name": "root",
            "children": [
                {
                    "2": {
                        "name": "fish",
                        "children": [] // empty children
                    }
                },
                {
                    "3": {
                        "name": "bird",
                        "children": [ ...<any children>... ]
                    }
                }
            ]
        }
    }
]

when I do ctx.body = tree this is what the api returns:

{
    "root": {
        "_id": "1",
        "name": "root",
        "children": [
            {
                "_id": "2",
                "name": "fish",
                "children": []
            },
            {
                "_id": "3",
                "name": "bird",
                "children": []
            }
        ]
    },
    "treeNodeMap": {}
}

What would be the right way to convert it to the desired json format?

CodePudding user response：

Have your classes implement toJSON() to produce the data structure you want.

// Define the data structure
interface SerialisedNode {
  [id: string]: {
    name: string;
    children: SerialisedNode[]
  }
}

class Node {
  private _id: string;
  name: string;
  parent?: Node;
  children: Node[];

  toJSON(): SerialisedNode {
    return {
      [ this._id ]: {
        name: this.name,
        children: this.children.map(node => node.toJSON())
      }
    }
  }
}

class Tree {
  root: Node;
  treeMap: Map<string, Node>;

  toJSON(): SerialisedNode {
    return this.root.toJSON();
  }
}

When your Tree (or any Node) is stringified as JSON, the transform will kick in and deliver the alternate data structure.

TypeScript Playground Demo