How to speedup the warm-up time of ts-node?

[sebastianrath]

Hello, I am using ts-node in the repo SnowFS.

SnowFS is a command-line application written in TypeScript and during unit-tests, I use a batch/shell script to verify the functionality of the program, as sketched below.

On Windows: snowfs.bat
On macOS and Linux: snowfs

As you can see from the sketch above, several tests execute snow.bat which uses ts-node. Every single call fires up ts-node. I found several posts and questions about the warmup time of ts-node, but most of them are outdated. What would be the most current way to speedup the warm-up time ot ts-node?

As you can see, the unit-tests take very long, for just a few calls (full log here)

9.cli.ts snow add bar.txt (10s) 
9.cli.ts snow rm foo.txt (25.2s) 
9.cli.ts snow rm subdir (24.9s) 
...

Any help is highly appreciated!

[cspotcode]

Are you using transpileOnly mode? You can configure ts-node options within your tsconfig file: https://github.com/Snowtrack/SnowFS/blob/main/tsconfig.json

The website linked below is still a work-in-progress, but this page explains configuration:
https://typestrong.org/ts-node/docs/configuration

Remember that many people believe ts-node must do typechecking, but this is usually not true. It is actually better to use tsc with the noEmit option to typecheck once before your tests run. ts-node can skip typechecking.

[dguard]

@seb-mtl, thank you, man
time reduced from 11 sec to 5 sec

[cspotcode]

FYI this has since been simplified greatly. Check out our "swc": true option, which is even faster than transpileOnly.

https://typestrong.org/ts-node/docs/swc

[dguard]

@cspotcode
I am using this executable in nodemon.json

ts-node -r tsconfig-paths/register src/main.ts

added in tsconfig.json

{
  "ts-node": {
    "swc": true
  },
}

my tsconfig.json

{
  "ts-node": {
    "swc": true
  },
  "compilerOptions": {
    "module": "commonjs",
    "declaration": true,
    "removeComments": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es2017",
    "sourceMap": false,
    "outDir": "./dist",
    "baseUrl": "./src",
    "incremental": true,
    "paths": {
      "@components/*": ["components/*"],
      "@endpoints/*": ["endpoints/*"]
    }
  },
  "exclude": ["node_modules", "dist"]
}

but it not works, what is wrong?

[cspotcode]

That configuration is correct and does work. There must be something else that is wrong that you did not include in your question.

[dguard]

@cspotcode, cool it was also required
yarn add ts-node
and it works

4 sec