CODEWITHSUNDEEP
nestjs
user2587202
user2587202

Reputation: 41

Use NestJs package in nodejs/express project

I developed a nest JS module. I published that on npm using npm publish.

Now i would like to use that NestJS module in a project built on nodejs and express.

Please advise if I can use a nestjs Module in node/express project. If yes is there any documentation available on that.

As per comment from User adding few more details.

This is kind of Library which is having a module with few methods exported. These method contains implementation which calls aws sns service to send push notification.

I found a link now trying to use that.

https://codeburst.io/https-chidume-nnamdi-com-npm-module-in-typescript-12b3b22f0724

Thanks in advance.

Upvotes: 1

Views: 5791

Answers (3)

Eylon
Eylon

Reputation: 761

You can use ExpressAdapter to host express application inside your nest.js application.

import { NestFactory } from '@nestjs/core'
import { SubAppModule } from './sub-app/module'
import {ExpressAdapter} from "@nestjs/core/adapters/express-adapter";
import {expressApp} from "./expressApp";

async function bootstrap () {
  const app = await NestFactory.create(SubAppModule, new ExpressAdapter(expressApp))
  app.listen(4444)
  return app
}

bootstrap()

you might see the full example based on @Jesús Franco original example: https://github.com/eylonmalin/nestjs-graphql-as-express-subapp

Upvotes: 0

user2587202
user2587202

Reputation: 41

Just for Update.

I exported method inside main.ts/index.ts whichever file is your entry point.

After that i did

1: npm run build 2: npm publish.

After doing this when i installed published package inside another project of express/nest, i was able to call methods.

Thanks

Upvotes: 0

Jesús Franco
Jesús Franco

Reputation: 316

Because a NestJS Module is itself a module for an express app, what you could do to make that module usable inside another app that is not using currently NestJS, is to mount it as a sub app.

I've build a NestJS module and mounted it as a subapp of a vanilla express app, you could borrow from my example test here: https://github.com/tzkmx/nestjs-graphql-as-express-subapp

The key is exporting your Module as a sub app already initialized, you could not mount the modue directly inside another express app without using the NestJS framework itself in it.

// src/sub-app/boot.js
import { NestFactory } from '@nestjs/core'
import { SubAppModule } from './module'

export default async function bootstrap () {
  const app = await NestFactory.create(SubAppModule)

  return app
}

// src/app.js
import bootstrapSubApp from './sub-app/boot'
import express from 'express'

const app = express()

app.get('/', (req, res) => res.send('hello express\n'))

async function mountSubApp (app, mountPath, subAppBoot) {
  const subApp = await subAppBoot()
  await subApp.init()

  app.use(mountPath, subApp.getHttpAdapter().getInstance())
  return app
}

mountSubApp(app, '/sub', bootstrapSubApp)
.then(app => app.listen(4000))

As you can see, it is needed first call subApp.init() and then getting the express instance with subApp.getHttpAdapter().getInstance() to mount it in the vanilla js express app.

Upvotes: 8

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