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Developing an Express Application Using TypeScript

Itachi Uchiha on November 03, 2019

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 th...
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nickytonline profile image
Nick Taylor • • Edited

One thing you could do is also add nodemon into the mix.

GitHub logo remy / nodemon

Monitor for any changes in your node.js application and automatically restart the server - perfect for development

Nodemon Logo

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 use nodemon, replace the word node on the command line when executing your script.

NPM version Travis Status Backers on Open Collective Sponsors on Open Collective

Installation

Either through cloning with git or by using npm (the recommended way):

npm install -g nodemon
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And nodemon will be installed globally to your system path.

You can also install nodemon as a development dependency:

npm install --save-dev nodemon
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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 using npx nodemon.

Usage

nodemon wraps your application, so you…

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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 your npm start script. The reason being is it is a debugging/dev tool, much like babel-node. Consider transpiling and running the dist/server.js with good ol' node.

Looking forward to your next post!

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itachiuchiha profile image
Itachi Uchiha •

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 :)

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heritiermwalila profile image
Heritier Mwalila •

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.

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edportscher profile image
Edwin •

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)

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heritiermwalila profile image
Heritier Mwalila •

@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

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Sufian Babri •

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 type NextFunction:

const loggerMiddleware = (req: Request, resp: Response, next) => {
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So, to import NextFunction, you can replace import { Request, Response } from 'express' with:

import { Request, Response, NextFunction } from 'express'
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jappyjan profile image
jappyjan •

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.

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Itachi Uchiha •

I didn't know Ts.ED. It's amazing. ❤

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jmicaela profile image
jmicaela •

Hey this is amazing starter code

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Alex van der Valk •

Thanks for this tutorial. I managed to implement this with handlebars instead.

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wh1337 profile image
wh1337 •

Thank you for the tutorial. Saved me hours of rummaging around google searches!

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Josias Aurel •

Thanks for this informative post :thumbUp:

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andymwamengo profile image
Andongwisye Mwamengo •

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

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M1 Tech •

Great Tutorial, learned a lot from it.!!