Node-Typescript

Steps to Initiate Typescript With Node

Step 1

• Run sudo npm i -g typescript to install typescript globally.
• Check typescript version by running tsc --version to make sure you installed it correctly.

Step 2

• Create a file called app.ts touch app.ts
• Write typescript code in it.
• To compile it run tsc app.ts. It will generate an actual Javascript file for app.js.
• If you want to watch your ts file every time when changes happen, run tsc app.ts -w.

Step 3

• Create a typescript config file by running tsc --init. This will generate a tsconfig.json file with commented options.
• Make the "target" to es2016
• Uncomment "outDir": "./" and "rootDir": "./".
• Add ./dist to outDir. "outDir": "./dist": It will add the compiled js files into dist folder.
• Add ./src to rootDir. "rootDir": "./src": It will specify the root directory of input files.
• Make sure to uncomment the "moduleResolution": "node"

Step 4

• Now move the app.ts file into src folder.
• Simple run tsc in the project directory to automatically create a dist folder and add the compiled version of app.ts.

Step 5

• Add package.json file by running npm init -y.
• Install express: npm i express.
• Run npm i -D typescript ts-node nodemon @types/node @types/express to install typescript, ts-node, nodemon, types definition of node and express as Dev dependencies.

Step 6

Add Below as Scripts in package.json file

• "start":"node dist/app.js",
• "dev": "nodemon --exec ts-node src/app.ts",
• "build": "tsc -p ."

Finally

Run npm run dev to start development, after you finish your work, you can run npm run build to compile the files inside the src folder into javascript files (create a dist folder to store them). In short, the src folder contains the typescript files and the dist folder contains the compiled (into javascript) version of typescript files.