What's the difference between tsc (TypeScript compiler) and ts-node?

Question

I'm very confused about the difference between tsc and ts-node. I'm learning TypeScript and I usually transpile server .ts files with tsc command.

Now, I'm approaching nestjs framework, and I see that it uses ts-node.

So what's the difference between the two? Which one should I use?

Solution 1

The main difference is that tsc transpile all the file according to your tsconfig. Instead, ts-node will start from the entry file and transpile the file step by step through the tree based on the import/export

Solution 2

Most common practice is that tsc is used for production build and ts-node for development purposes running in --watch mode along with nodemon. This is a command i often use for development mode for my node/typescript projects:

"dev": "nodemon -w *.ts -e ts -x ts-node --files -H -T ./src/index.ts"

Comments

[gremo]

@jfriend00 can you elaborate your answer? AFAIK tsc will change import to the commonjs require(), which in turn will load the JavaScript source file (assuming in node_modules).

[jfriend00]

Read the first paragraph here: npmjs.com/package/ts-node

[Michael Freidgeim]

Some discussion at reddit.com/r/typescript/comments/8vkvzy/…

[Krimson]

So which one to use and when?

[Adrien De Peretti]

Its a better practice to use tsc to build your project and then run it with node in production, its also faster

[TetraDev]

Sometimes you only need to compile one entrypoint and it's imports - ts-node is perfect for that and has no downsides.

[Jeremy]

i think that there is a ts-node-dev package which speeds build times up if performance is an issue

[sotn]

tsc --watch could've also been used which uses incremental builds and is faster than nodemon..

[Es Noguera]

I'm wondering which builder should I use to build react applications nowadays

[Molten Ice]

Quick update on this, ts-node CAN be used in production: stackoverflow.com/questions/60581617/… and there's a faster way than using nodemon: npmjs.com/package/ts-node-dev