querybuilder

@Injectable()
export class QueryBuilder<T> {
    private queryString: string;
    private postObject: Object;
    private method: string;
    private controller: string;
    constructor(public http: HttpHandler) {
    }
    public Query(controller: string): this {
        this.controller = controller;
        this.method = 'GET';
        return this;
    }
    public Include(inc: string | Object): this {
        if (typeof inc === 'string') {
            this.queryString += 'id=' + inc + '&';
            this.method = 'GET';
        }
        else if (typeof inc === 'object') {
            this.method = 'POST';
            this.postObject === inc;
        }
        return this;
    }
    public Add(obj: T): this {
        this.postObject = obj;
        this.method = 'POST';
        return this;
    }
    public Remove(id: string): this {
        this.queryString += 'id=' + id + '&';
        this.method = 'DELETE';
        return this;
    }
    public async Execute(): Promise<T | Array<T>> {
        let res: Response;
        switch (this.method) {
            case 'GET':
                res = await this.http.Get(this.controller + '?' + this.queryString);
                break;
            case 'POST':
                res = await this.http.Post(this.controller, this.postObject);
                break;
            case 'DELETE':
                res = await this.http.Post(this.controller, this.postObject);
                break;
        }
        return res.json();
    }
}