This post was first published on my blog.
Recently, I was working on TypeScript. I asked a question about TypeScript. Dev users helped me.
In this post, I'll show you how to create an express application using TypeScript.
Before you start, I'm so sorry for my grammar mistakes.
Express Framework
As you know, Express is a NodeJS web framework that works on the server.
Installation of Dependencies
npm i express pug ts-node typescript @types/express @types/node
These are dependencies.
Edit package.json and tsconfig.json files
The scripts section in the package.json will be like that;
"scripts": {
"dev": "ts-node src/server.ts",
"start": "ts-node dist/server.js",
"build": "tsc -p ."
}
I'll be able to run the dev version of this application using the npm run dev
command.
My tsconfig.json file will be like that;
{
"compilerOptions": {
"sourceMap": true,
"target": "es6",
"module": "commonjs",
"outDir": "./dist",
"baseUrl": "./src"
},
"include": [
"src/**/*.ts"
],
"exclude": [
"node_modules"
]
}
Project Structure
This is our project structure;
- dist
- node_modules
- public
- src
- views
package.json
tsconfig.json
By the way, public and views folders are not necessary if you don’t need UI in your project. (For example API backend). The project will develop under the src folder.
- controllers
- interfaces
- middleware
app.ts
server.ts
The controllers folder will have route controllers and their interface files. The interfaces folder will have interface files. The middleware folder will have our middlewares.
Let's look at the app.ts and server.ts files
Application File src/(app.ts)
My application file is like that;
import * as express from 'express'
import { Application } from 'express'
class App {
public app: Application
public port: number
constructor(appInit: { port: number; middleWares: any; controllers: any; }) {
this.app = express()
this.port = appInit.port
this.middlewares(appInit.middleWares)
this.routes(appInit.controllers)
this.assets()
this.template()
}
private middlewares(middleWares: { forEach: (arg0: (middleWare: any) => void) => void; }) {
middleWares.forEach(middleWare => {
this.app.use(middleWare)
})
}
private routes(controllers: { forEach: (arg0: (controller: any) => void) => void; }) {
controllers.forEach(controller => {
this.app.use('/', controller.router)
})
}
private assets() {
this.app.use(express.static('public'))
this.app.use(express.static('views'))
}
private template() {
this.app.set('view engine', 'pug')
}
public listen() {
this.app.listen(this.port, () => {
console.log(`App listening on the http://localhost:${this.port}`)
})
}
}
export default App
As you can see, the constructor expects three parameters. In this logic, port and controller parameters should be required but I wasn't sure about it. I've also init the assets and templates in case you use the UI in your project.
Server File src/(server.ts)
My server file is like that;
import App from './app'
import * as bodyParser from 'body-parser'
import loggerMiddleware from './middleware/logger'
import PostsController from './controllers/posts/posts.controller'
import HomeController from './controllers/home/home.controller'
const app = new App({
port: 5000,
controllers: [
new HomeController(),
new PostsController()
],
middleWares: [
bodyParser.json(),
bodyParser.urlencoded({ extended: true }),
loggerMiddleware
]
})
app.listen()
In this file, we've imported our App class. We passed three parameters. The first one port number. Our app will run on port 5000.
The second one is the controllers parameter. Our controller classes will be here with the new keyword.
And the last one middleWares. If you're using bodyParser or similar plugins you can use the middleWares.
Our Simple Middleware (middleware/logger.ts)
import { Request, Response } from 'express'
const loggerMiddleware = (req: Request, resp: Response, next) => {
console.log('Request logged:', req.method, req.path)
next()
}
export default loggerMiddleware
This is a simple HTTP logger. It shows the HTTP verb and its path.
IControlerBase (interfaces/IControllerBase.interface.ts)
I thought so that every controller has to implement this interface.
interface IControllerBase {
initRoutes(): any
}
export default IControllerBase
Our First Controller (controllers/home.controller.ts)
HomeController will be like that;
import * as express from 'express'
import { Request, Response } from 'express'
import IControllerBase from 'interfaces/IControllerBase.interface'
class HomeController implements IControllerBase {
public path = '/'
public router = express.Router()
constructor() {
this.initRoutes()
}
public initRoutes() {
this.router.get('/', this.index)
}
index = (req: Request, res: Response) => {
const users = [
{
id: 1,
name: 'Ali'
},
{
id: 2,
name: 'Can'
},
{
id: 3,
name: 'Ahmet'
}
]
res.render('home/index', { users })
}
}
export default HomeController
We've implemented the IControllerBase. So, we must follow its rules. In this example controller file, we're assuming that we have data from the database server. I sent this data to the (home/index.pug) file. This file is located under the views folder.
<!DOCTYPE html>
html(lang="en")
head
meta(charset="UTF-8")
meta(name="viewport", content="width=device-width, initial-scale=1.0")
meta(http-equiv="X-UA-Compatible", content="ie=edge")
title Document
body
each user, index in users
h2(onclick=`alert(${index})`)= user.name
This is our pug file. We've also implemented the initRoutes
method. Because the boss(IControllerBase) wants that.
Let's start the app
npm run dev
With this command, we will be able to run our application. Our application works on http://localhost:5000
.
You can also check the posts folder. In this project, you can use TypeORM or Sequelize.
You can find this project on GitHub: https://github.com/aligoren/express-typescript-test
Conclusion
I really loved to use TypeScript. Before this work, I never had an idea about how TypeScript works.
Thanks for reading.
Top comments (14)
One thing you could do is also add nodemon into the mix.
remy / nodemon
Monitor for any changes in your node.js application and automatically restart the server - perfect for development
nodemon
nodemon is a tool that helps develop node.js based applications by automatically restarting the node application when file changes in the directory are detected.
nodemon does not require any additional changes to your code or method of development. nodemon is a replacement wrapper for
node
. To usenodemon
, replace the wordnode
on the command line when executing your script.Installation
Either through cloning with git or by using npm (the recommended way):
And nodemon will be installed globally to your system path.
You can also install nodemon as a development dependency:
With a local installation, nodemon will not be available in your system path. Instead, the local installation of nodemon can be run by calling it from within an npm script (such as
npm start
) or usingnpx nodemon
.Usage
nodemon wraps your application, so you…
There are VS Code recipes to handle this.
Specifically this one, github.com/microsoft/vscode-recipe...
Even if you don't use VS Code, the tips provided are still helpful (see the npm scripts in the repo).
One thing I would recommend is to not use
ts-node
for production as you currently are for yournpm start
script. The reason being is it is a debugging/dev tool, much likebabel-node
. Consider transpiling and running thedist/server.js
with good ol' node.Looking forward to your next post!
Thanks, Nick.
I'm usually using the VS Code. I never heard the vscode-recipes before.
I'm trying to best :)
I don't remember clearly but I may have used nodemon before. It worked so slow on my computer. I know, it depended on my computer. I use a really old laptop.
Again I will say, these recipes are really helpful to me.
Thanks :)
Hey Ali, thanks for the post I've learned something as I am new to typescript.
I just found that if you want to import express instance you must do it this way
import express from 'express' not import * as express from 'express'
Typescript detect that as an error.
I have a question, I am just learning typescript, I do not understand this.
private middlewares(middleWares: { forEach: (arg0: (middleWare: any) => void) => void; })
what does { forEach: (arg0: (middleWare: any) => void) => void; } this do?
why could you not do this?
private middlewares(middleWares: any)
@edwin , this is very easy to understand if you already understand type of interface in typescript
You can write the same thing like this
interface arg{
(ar)=>void
}
interface middlewareInter{
forEach:(argument:arg)=>void // look at forEach function in js how it written
}
private middlewares(middlew:middlewareInter){
}
it return void because don't wanna handle the result there. void is a type in typescript which just tell that the function does not return anything
Nice article. I've got a question and a suggestion. :)
The question: your "start" script is using ts-node, shouldn't it use node because it'd be an overkill otherwise? Maybe some performance issue?
The suggestion: in the following line, instead of not declaring the type of the parameter "next" which defaults to
any
, you can declare it of typeNextFunction
:So, to import
NextFunction
, you can replaceimport { Request, Response } from 'express'
with:When using express with typescript, the best u can do is to take a look into TS.ed.
For me, this is the absolute best solution, with decorators and a fairly great architecture.
I didn't know Ts.ED. It's amazing. ❤
Hey this is amazing starter code
Thanks for this tutorial. I managed to implement this with handlebars instead.
Thank you for the tutorial. Saved me hours of rummaging around google searches!
Thanks for this informative post :thumbUp:
I had some issue with the setup of the express typescript project, But this is an enterprise level setup of the project.
Thank you keep writing good stuffs like this