我决定创建一个没有任何ORM的项目,仅使用mysql2程序包+ node(typescript),但是我在下面很难解决这个问题:
TypeError: Cannot read property 'userService' of undefined
当我尝试调用get路由/ api / user时出现此错误,但是该服务正在我的控制器类上初始化。我只测试了查询,并按预期返回了所有内容。
我项目的主要结构将具有用于数据库查询的repository,用于业务逻辑的service和将管理我的路线的controller。
用户存储库
import pool from './../config/db';
interface IUser {
id: number,
login: string,
created_at: Date,
updated_at: Date
}
class User {
async getUsers (): Promise<Array<IUser>> {
try {
const [rows]: [Array<IUser>] = await pool.query('SELECT * FROM `clients`', []);
return rows;
} catch (err) {
return err;
}
}
}
export default User;
UserService
import User from './../repository/user';
class UserService {
private user;
constructor () {
this.user = new User();
}
getUsers () {
return this.user.getUsers();
}
}
export default UserService;
UserController
import UserService from '../services/user.service';
import express from 'express';
class UserController {
public path = '/user';
public router = express.Router();
public userService;
constructor () {
this.userService = new UserService();
this.initializeRoutes();
}
private initializeRoutes (): void {
this.router.get(this.path, this.get);
}
get (req, res) {
res.send(this.userService.getUsers());
}
}
export default UserController;
并且在我的主文件中,我有此方法将调用路由:
private routes (): void {
const routes = [
new UserController()
];
routes.forEach((route) => {
this.app.use('/api', route.router);
});
}
在UserController中,get
类方法功能由路由器调用。因此,您应该将get
函数绑定到类实例映射器,这样将其绑定到this
: