How to Restart the TypeScript NodeJS Application Fast

I have been working for the different kinds of Node JS application from the last 4 years. For every project I tried to improve the performance and code quality. From that, I found a very interesting way to restart the typescript application so fast.

Introduction

When you are working with Node JS with Typescript you notice a significant delay while restarting the application by using ts-node.

ts-node

Typical Typescript NodeJS App

A typical nodejs-typescript

nodemon.json 

{
    "watch" : ["src"],
    "ext" : "ts",
    "exec": "ts-node ./src/app/server.ts"
}

It will work fine but restart speed is too slow.

Don't trust the Server Start time here, it actually took more than 20 seconds to restart.

Trail 1

So I was playing with the nodemon options to make restart faster and found we map our executable with params, so I create this configuration for

nodemon.json

{
  "env": {
    "NODE_ENV": "development"
  },
  "execMap": {
    "ts": "node --require ts-node/register"
  },
  "ext": "js,json,ts",
  "ignore": [
    ".git",
    "node_modules/**/node_modules"
  ],
  "restartable": "rs",
  "watch": [
    "src/"
  ]
}

This increase the restarting speed, but that not enough for me. So again I started to digging through Google to find better ways.

Trail 2

Now I learned to diagnosis typescript and analysis my project by using this command:

./node_modules/.bin/tsc -project ./tsconfig.json --diagnostics

This gives an output like these:

Files:              372
Lines:            66423
Nodes:           253384
Identifiers:      89381
Symbols:          62938
Types:             3327
Instantiations:    7640
Memory used:    108724K
I/O read:         0.98s
I/O write:        0.02s
Parse time:       2.20s
Bind time:        0.40s
Check time:       0.29s
Emit time:        0.16s
Total time:       3.04s

I found

tsc

parse time

Instead of using

ts-node

tsc

{
"dev": "concurrently \"tsc -w\" \"nodemon dist/app/server.js\""
}

This improves the restarting speed significantly

Trail 3

tsc

ts-node-dev 

This significantly increases the speed of restarting comparing to 

nodemon -x ts-node

Step 1: Install the package

npm i ts-node-dev --save-dev

Step 2: Add Configuration

{
    "dev": "node_modules/.bin/ts-node-dev --respawn --notify false --prefer-ts --ignore-watch node_modules -- src/app/server.ts "

}

This is the exact configuration I used in my project, this works very fine to me.

Step 3: Starts the application

npm run dev

This will restart the application every time you change a file with blazing speed.

Conclusion

After testing a lot of tool for developing typescript-nodejs I found the ts-node-dev work like a pro. I recommend to everyone to use the

ts-node-dev

If you stick this far, thank you so much for reading this article and please consider to follow me on twitter