TypeScript: Week Reflection

export class ReflectMemberInfo {
    constructor(public name:string, public type: string, public isArray: boolean) {
    }
}

export class WeekReflector {
    members: ReflectMemberInfo[] = [];
    reflect(obj: any): void {
        JSON.stringify(obj, (key, value) => {
            if (key == '') {
                // it is the root object
                return value;
            }

            var isArray = (value instanceof Array);
            this.members.push(new ReflectMemberInfo(key, typeof(value), isArray));
            return null;
        });
    }
}

// Test
class TestObject {
    memberBoolean: boolean = false;
    memberNumber: number = 1;
    memberString: string = "Jack";
    // memberSymbol: Symbol = Symbol();
    memberUndefined?: string = undefined; // type is undefined
    memberNull: string | null = null;   // type is object
    memberCannotFound: string;      // cannot be reflected
    memberObject: TestNestedObject = new TestNestedObject();
    // type is object
    memberStringArray: string[] = ["A", "B", "C"];      
    // type is object
    memberObjectArray: TestNestedObject[] = [new TestNestedObject(), new TestNestedObject()];
    // type is function
    memberFunction: Function = () => {};
    // cannot be reflected
    public normalFunc(): any {
        return null;
    }
    
}

class TestNestedObject {
    nestedNumber: number = 2;
    nestedString: string = "Mike";
    nestedNull: string | null = null;
    nestedUndefined?: string = undefined;
    nestedStringArray: string[] = ["A", "B", "C"];
}

var reflector = new WeekReflector();
reflector.reflect(new TestObject());
console.log(reflector.members);

[ ReflectMemberInfo { name: 'memberBoolean', type: 'boolean', isArray: false },
  ReflectMemberInfo { name: 'memberNumber', type: 'number', isArray: false },
  ReflectMemberInfo { name: 'memberString', type: 'string', isArray: false },
  ReflectMemberInfo { name: 'memberUndefined', type: 'undefined', isArray: false },
  ReflectMemberInfo { name: 'memberNull', type: 'object', isArray: false },
  ReflectMemberInfo { name: 'memberObject', type: 'object', isArray: false },
  ReflectMemberInfo { name: 'memberStringArray', type: 'object', isArray: true },
  ReflectMemberInfo { name: 'memberObjectArray', type: 'object', isArray: true },
  ReflectMemberInfo { name: 'memberFunction', type: 'function', isArray: false } ]