如何通过不使用新关键字运行NodeJS项目

Question

I am developing a NodeJS project by using TypeScript. But I can't figure out how to run app.ts file by using class.

How to run Root class without new keyword ? That is the point.

App.TS

// Express
import { application as app } from 'express';

// Controllers
import { UserController } from './controllers/user.controller'

export class App {
  constructor(userController: UserController) {
    console.log("App is running");
    console.log("UserController url path is : ", userController.getUrlPath);
  }

  run(): void {
    app.listen(3000, function () {
      console.log('App is running on port 3000!');
    });
  }
}

Root.TS

import { App } from "../app";

export class Root {
    constructor(application: App) {
        application.run();
    }
}

How to run Root class without new keyword ? That is the point.

Because it has to get instances of parameters of its constructor with dependency injection.

Compiler start code :

ts-node-dev --respawn --transpileOnly ./app/root.ts

This code tries to run root.ts file's code. There is a Root class but there is no created object of class. So, there is no runnable class or method.

Answer 1

You cannot "execute" a .ts file with Node.JS, you need to compile it first in JavaScript. Use the typescript module to do this: npm i -s typescript

Then run the command tsc in your terminal.

Answer 2

To execute TS files you can simply install and use ts-node , it has all the same behaviour as a normal node but will transpile any file needed.

This way you won't even need to transpile your code before running it.