Building a RESTful API with TypeScript and Express

Creating an efficient and powerful RESTful API can be a daunting task. Using TypeScript and Express, you’re able to rapidly and reliably build robust, feature-rich APIs. With the support of the TypeScript language, you’ll be able to produce faster code, better scalability, and higher quality.

TypeScript is a strongly typed, object-oriented programming language that has been built on top of JavaScript. Because of this, you have access to all the features of JavaScript while also having the ability to use additional features like type safety, generics, enums, and classes.

Express is a Node.js framework used to build web applications and APIs. Express provides you with a great deal of flexibility and an extensive range of tools that can help you to quickly create APIs.

In this article, we’ll discuss the process of building a RESTful API using TypeScript and Express.

Step 1: Setup the Project

The first step is to create a new project by initializing a new npm project. This can be done by running the following command in the terminal.

npm init

The project should be scaffolded and the package.json file should be created. At this point, you should install some of the dependencies for the project.

Step 2: Install the Dependencies

Install the following dependencies:

npm install express nodemon typescript @types/express @types/node --save-dev

• express: A Node.js web application framework.
• nodemon: This is a tool that is used to automatically restart the server whenever there is a change in the project files.
• Typescript: A strongly typed, object-oriented programming language used to build web applications.
• @types/express and @types/node: These are type definitions for Express and Node.

Step 3: Create the TypeScript Configuration File

The next step is to create a configuration file for TypeScript. This is done by running the tsc --init command. This will create a tsconfig.json file in the root of the project.

{
  "compilerOptions": {
    "target": "ES6",
    "module": "commonjs",
    "outDir": "./dist",
    "allowJs": true,
    "strict": true
  },
  "include": [
    "./src/**/*"
  ]
}

Step 4: Setup the Server

The next step is to create an Express server. Create a folder called src in the root and create a file called index.ts inside the folder. This will be the entry point of the application.

Inside the index.ts file, add the following code.

import express, {Application} from 'express';

const app: Application = express();

app.get('/', (req, res) => {
  res.send({message: "Hello World"});
});

app.listen(3000, () => {
  console.log("Server is running on port 3000");
});

The code above creates an Express server that listens on port 3000 and returns a simple Hello World message when the root route is accessed.

Step 5: Build the Project

The final step is to build the project using Typescript. This can be done by running the following command.

tsc

This will compile the TypeScript code and will generate the JavaScript files inside a dist folder.

Step 6: Run the Project

At this step, you can run the project using the node command.

node dist/index.js

The server will start running and you’ll be able to access it at http://localhost:3000.

Conclusion

Creating a RESTful API using TypeScript and Express can be an enjoyable and efficient experience. By following the steps above, you’ll be able to quickly and reliably create an API that is reliable, secure, and highly scalable.