How to watch and reload ts-node when TypeScript files change

Question

I\'m trying to run a dev server with TypeScript and an Angular application without transpiling ts files every time. I found that I can do the running with ts-node

Answer 1

I've dumped nodemon and ts-node in favor of a much better alternative, ts-node-dev https://github.com/whitecolor/ts-node-dev

Just run ts-node-dev src/index.ts

Answer 2

Here's an alternative to the HeberLZ's answer, using npm scripts.

My package.json:

  "scripts": {
    "watch": "nodemon -e ts -w ./src -x npm run watch:serve",
    "watch:serve": "ts-node --inspect src/index.ts"
  },

• -e flag sets the extenstions to look for,
• -w sets the watched directory,
• -x executes the script.

--inspect in the watch:serve script is actually a node.js flag, it just enables debugging protocol.

Answer 3

Specifically for this issue I've created the tsc-watch library. you can find it on npm.

Obvious use case would be:

tsc-watch server.ts --outDir ./dist --onSuccess "node ./dist/server.js"

Answer 4

Add "watch": "nodemon --exec ts-node -- ./src/index.ts" to scripts section of your package.json.

Answer 5

you could use ts-node-dev

It restarts target node process when any of required files changes (as standard node-dev) but shares Typescript compilation process between restarts.

Install

yarn add ts-node-dev --dev

and your package.json could be like this

"scripts": {
  "test": "echo \"Error: no test specified\" && exit 1",
  "tsc": "tsc",
  "dev": "ts-node-dev --respawn --transpileOnly ./src/index.ts",
  "prod": "tsc && node ./build/index.js"
}

Answer 6

add this to your package.json file

scripts {
"dev": "nodemon --watch '**/*.ts' --exec 'ts-node' index.ts"
}

and to make this work you also need to install ts-node as dev-dependency

yarn add ts-node -D

run yarn dev to start the dev server