Day17.md

Building Lynkit - URL Shortener Day 1 : Setting up ExpressJS Server with Typescript

Lynkit will be a full stack URL shortener application built using ReactJS, NodeJS, Typescript, MongoDB and Redis for caching.

The first step is building the REST API using ExpressJS with Typescript and MongoDB.

Setup for ExpressJS to use Typescript

• Create a new folder and run :

npm init -y

This initialized an npm respository with default options.

• Next, step is to install the necessary dependencies to run Typescript.

📌 The dependencies needed for running Typescript will only be needed during development, so we will install them as DevDependencies using the following command :

npm install -D typescript nodemon ts-node

When these are installed, we need to configure the environment.

• Next, we need to configure typescript, so create a new file : tsconfig.json in the root directory and add the following :

  {
    "compilerOptions" : {
        "module": "Node16", //Specifies the target module system - ensures generated code is compatible with Node.js
        "moduleResolution": "node", // Determines how compiler resolves module imports - uses Node.js resolution strategy
        "baseUrl": "src", // sets the base directory for module resolution
        "outDir": "dist", // generated JavaScript files will be placed in the dist directory
        "sourceMap": true, // Source maps enable browser debugging of transpiled TypeScript
        "noImplicitAny": true // throws an error if TypeScript cannot determine the type of a variable
    },
    "include": ["src/**/*"] // specifies which files to include in the compilation process, set to include all TypeScript files under the src directory and its subdirectories
  }

• Now we need to configure nodemon to run with typescript. Create a nodemon.json file and add the following code :

{
    "watch" : ["src"], // which folder to watch for changes
    "ext" : ".ts,.js", // which extensions to watch for changes to restart the server
    "exec" : "ts-node ./src/index.ts" // the script nodemon execute
}

And there you have it, you are ready to develop your express server in typescript.