Dependencies not being injected on NestJS with Serverless and AWS - serverless-framework

Question

Everyone,
I'm trying to setup my first NestJS application. It is backed by Serverless on AWS.
I created a simple Controller that has a Service as a dependency. When I hit the endpoint with my HTTP Client, the object that should contain the Service instance is undefined. I'm not able to make it work. Could you help?
handler.ts
import { Context, Handler } from 'aws-lambda';
import { NestFactory } from '#nestjs/core';
import { AppModule } from './src/module';
import { Server } from 'http';
import { ExpressAdapter } from '#nestjs/platform-express';
import * as serverless from 'aws-serverless-express';
import * as express from 'express';
import {DB} from './src/libs/db';
let cachedServer: Server;
function bootstrapServer(): Promise<Server> {
const expressApp = express();
const adapter = new ExpressAdapter(expressApp);
return NestFactory.create(AppModule, adapter)
.then(app => app.enableCors())
.then(app => app.init())
.then(() => DB.connect())
.then(() => serverless.createServer(expressApp));
}
export const handle: Handler = (event: any, context: Context) => {
if (!cachedServer) {
bootstrapServer().then(server => {
cachedServer = server;
return serverless.proxy(server, event, context);
});
} else {
return serverless.proxy(cachedServer, event, context);
}
};
module.ts
import { Module } from '#nestjs/common';
import { EventController } from './event.controller';
import { EventService } from './event.service';
#Module({
controllers: [EventController],
providers: [EventService],
})
export class AppModule {}
event.service.ts
import { Injectable } from '#nestjs/common';
interface Event{}
#Injectable()
export class EventService {
create(event: Event) {
return {
id: Date.now()
}
}
}
event.controller.ts
import { Controller, Post, Body } from '#nestjs/common';
import { EventService } from './event.service';
interface Event { }
#Controller('event')
export class EventController {
constructor(private readonly eventService: EventService) { }
#Post()
async create(#Body() req)
{
this.eventService.create(req);
}
}
So this.eventService is always undefined. What is wrong with this implementation?

Answer 1

Maybe you are missing a line from tsconfig add this below:
"emitDecoratorMetadata": true
Credits to the God of Nestjs Mr. Kamil's reply:
https://stackoverflow.com/a/50121886/6301493