Modeling from JSON in Typescript.

class Type {
    _kind: string;
    _breed: string;

    constructor(typeObj: any) {
        this._kind = typeObj.kind;
        this._breed = typeObj.breed;
    }
}

class Pet {
    private _name: string;
    private _age: number;
    private _type: Type;
    private _mealCount: number;

    constructor(petObj: any) {
        this._name = petObj.name;
        this._age = petObj.age;
        this._type = new Type(petObj.extra.type);
        this._mealCount = petObj.extra.meals.length;
    }

    getDescription = (): string =>
        `My ${this._name} is a ${this._type._breed} ${this._type._kind}.\n` +
        `She is ${this._age} year(s) old.\n` +
        `She takes ${this._mealCount} meal(s) everyday.`;
}




const pet: Pet = new Pet(JSON.parse(
    '{"name":"Fido","age":5,"extra":{"id":1234,"type":{"kind":"Cat","breed":"Parsian"},"meals":["Cat Food","Tuna Can","Boiled Chicken"]}}'
));

console.log(pet.getDescription());