Json to Object deeply

Question

In my TypeScript code I have 2 classes ClassA and ClassB:

export class ClassA {
    name: string;
    classB: ClassB;

    getName(): string {
        return this.name;
    }
}

export class ClassB {
    name: string;

    getName(): string {
        return this.name;
    }
}

I try to parse a Json into a ClassA instance like this:

let classA: ClassA = Object.assign(new ClassA(), JSON.parse('{"name":"classA", "classB": {"name":"classB"}}'));

But only ClassA is instanciated, inside classB attribute is not.

I have the following result when I log objects:

console.log(classA); // ClassA {name: "classA", classB: Object}
console.log(classA.getName()); // classA
console.log(classA.classB); // Object {name: "classB"}
console.log(classA.classB.getName()); // EXCEPTION: classA.classB.getName is not a function

Is that possible to deeply parse a Json?

Possible duplicate of [How do I cast a JSON object to a typescript class](http://stackoverflow.com/questions/22875636/how-do-i-cast-a-json-object-to-a-typescript-class) — Heretic Monkey, Mar 20 '17 at 16:47

Nitzan Tomer · Answer 1 · 2017-03-20T16:56:41.023

You'll need to do something like this:

export interface ClassBData {
    name: string;
}

export interface ClassAData {
    name: string;
    classB: ClassBData;
}

export class ClassA {
    name: string;
    classB: ClassB;

    constructor(json: ClassAData) {
        this.name = json.name;
        this.classB = Object.assign(new ClassB(), json.classB);
    }

    getName(): string {
        return this.name;
    }
}

Or you can instantiate ClassB the same way:

export class ClassB {
    name: string;

    constructor(json: ClassBData) {
        this.name = json.name;
    }

    getName(): string {
        return this.name;
    }
}

score 0 · Accepted Answer · answered Aug 25 '17 at 08:22

So far, the best way I found is to do:

export class ClassA {
    name: string;
    classB: ClassB;

    constructor(json: any) {
        this.name = json.name;
        if (json.classB !== undefined && json.classB !== null) {
            this.classB = new ClassB(json.classB);
        }
    }
}

export class ClassB {
    name: string;

    constructor(json: any) {
        this.name = json.name;
    }
}

Json to Object deeply

2 Answers2