是否有一种方法可以避免在每个服务中编写相同的代码。
我为不同的API端点提供多种服务:
getLecturesData(orderBy?: string, orderDirection = 'asc', page = 1, pageSize = 10): Observable<LecturesData> {
let params = new HttpParams();
params = params.set('order_direction', orderDirection);
params = params.set('page', page.toString());
params = params.set('page_size', pageSize.toString());
if (orderBy) { params = params.set('order_by', orderBy); }
return this.http.get<LecturesData>('/api/lectures', {params});
}
getStudentsData(orderBy?: string, orderDirection = 'asc', page = 1, pageSize = 5): Observable<StudentsData> {
let params = new HttpParams();
params = params.set('order_direction', orderDirection);
params = params.set('page', page.toString());
params = params.set('page_size', pageSize.toString());
if (orderBy) { params = params.set('order_by', orderBy); }
return this.http.get<StudentsData>('/api/students', {params});
}
您可以看到,代码几乎相同,除了返回值的url
和type
。是否可以将重复的部分放置在分离的“事物”中?
我将为参数创建一个接口,并创建一个私有的通用函数来发出请求。
export interface QueryOptions {
orderBy?: string;
orderDirection: string;
page: number;
pageSize: number;
}
getLecturesData(options: QueryOptions): Observable<LecturesData> {
return this.getData<StudentsData>('/api/lectures', options);
}
getStudentsData(options: QueryOptions): Observable<StudentsData> {
return this.getData<StudentsData>('/api/students', options);
}
private getData<T>(options: QueryOptions): Observable<T> {
const params: HttpParams = this.getOptionsParams(options);
return this.http.get<T>(url, {params});
}
private getOptionsParams(options: QueryOptions): HttpParams {
let params = new HttpParams();
params = params.set('order_direction', options.orderDirection || 'asc');
params = params.set('page', (page || 1).toString());
params = params.set('page_size', (pageSize || 10).toString());
if (orderBy) { params = params.set('order_by', orderBy); }
return params;
}