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[英]TypeError: Cannot read properties of undefined (reading 'prototype') React Typescript + Express
[英]express/tsyringe TypeError: Cannot read properties of undefined (reading 'service')
我正在为学校做一个小项目,我是表达和依赖注入的新手。 我开始这个小项目只是为了了解它是如何工作的。 几个小时以来,我一直试图理解这个错误,但我没有找到任何相关信息。 感谢您的帮助 !
TypeError: Cannot read properties of undefined (reading 'service')
at controllerMethod (D:\Projects\Typescript\third\dist\app.controller.js:20:14)
at Layer.handle [as handle_request] (D:\Projects\Typescript\third\node_modules\express\lib\router\layer.js:95:5)
at next (D:\Projects\Typescript\third\node_modules\express\lib\router\route.js:144:13)
at Route.dispatch (D:\Projects\Typescript\third\node_modules\express\lib\router\route.js:114:3)
at Layer.handle [as handle_request] (D:\Projects\Typescript\third\node_modules\express\lib\router\layer.js:95:5)
at D:\Projects\Typescript\third\node_modules\express\lib\router\index.js:284:15
at Function.process_params (D:\Projects\Typescript\third\node_modules\express\lib\router\index.js:346:12)
at next (D:\Projects\Typescript\third\node_modules\express\lib\router\index.js:280:10)
at Function.handle (D:\Projects\Typescript\third\node_modules\express\lib\router\index.js:175:3)
at router (D:\Projects\Typescript\third\node_modules\express\lib\router\index.js:47:12)
这是代码:
//app.ts
import express, { json, urlencoded } from 'express'
import { APPROUTE } from './app.route'
const app = express()
app.use(json())
app.use(urlencoded({ extended: false }))
app.use(APPROUTE)
app.listen(5000, ()=>{
console.log(`connected on port 5000`)
})
//app.controller.ts
import { Request, Response } from "express";
import { inject, singleton } from "tsyringe";
import { AppService } from "./app.service";
@singleton()
export class AppController{
constructor(@inject(AppService) private service: AppService){}
controllerMethod(req: Request, res: Response){
this.service.methodService()
}
}
//app.service.ts
import { singleton } from "tsyringe";
@singleton()
export class AppService{
methodService(){
console.log('service working')
}
}
//app.route.ts
import 'reflect-metadata'
import { Router } from "express";
import { container } from "tsyringe";
import { AppController } from "./app.controller";
export const APPROUTE = Router()
const controller: AppController = container.resolve<AppController>(AppController)
APPROUTE.get('/', controller.controllerMethod)
// package.json
{
"scripts": {
"start": "nodemon ./dist/app.js"
},
"devDependencies": {
"nodemon": "^2.0.16"
},
"dependencies": {
"@types/express": "^4.17.13",
"@types/node": "^18.0.0",
"dotenv": "^16.0.1",
"express": "^4.18.1",
"reflect-metadata": "^0.1.13",
"tsyringe": "^4.7.0"
}
}
//tsconfig.json
{
"compilerOptions": {
"target": "es6",
"experimentalDecorators": true,
"emitDecoratorMetadata": true,
"module": "commonjs",
"rootDir": "./src",
"outDir": "./dist",
"esModuleInterop": true,
"forceConsistentCasingInFileNames": true,
"strict": true,
"strictPropertyInitialization": false,
"skipLibCheck": true
}
}
只需将APPROUTE.get('/', controller.controllerMethod)
更改为APPROUTE.get('/', (req, res)=>controller.controllerMethod(req, res))
你在 JS 中一如既往地失去this
请尝试绑定
从:
identityRouter
.route('/login')
.post(
identityController.login
);
到:
const identityController = container.resolve(IdentityController);
identityRouter
.route('/login')
.post(
identityController.login.bind(identityController)
);
这里将确保这是注入/保持正确的方式:)
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