how to disable code inlining in vp pack for better debugging

[snebjorn]

I have a cli app

#!/usr/bin/env node

const greetingWords = ["hello", "world"];
const separator = " ";

console.log(greetingWords.join(separator));

I build it vp pack --sourcemap

it becomes:

#!/usr/bin/env node
//#region src/index.ts
console.log(["hello", "world"].join(" "));
//#endregion
export {};

//# sourceMappingURL=index.mjs.map

Notice greetingWords and separator are inlined.

I want to disable this for a better debugging experience when running it, for example via vp exec my-cli

Anyone know how?
Or what I'm really after is greetingWords and separator showing up when I'm debugging.

[cookesan]

That output is coming from the bundler, not from the source map flag. --sourcemap lets the debugger map generated code back to the original TypeScript, but it does not promise to preserve the generated JavaScript's local variables.

vp pack wraps tsdown, and the CLI exposes the relevant knobs:

vp pack --sourcemap --no-treeshake --unbundle

or in config:

export default defineConfig({
  pack: {
    sourcemap: true,
    treeshake: false,
    unbundle: true,
  },
})

If you still bundle into one file, Rolldown/tsdown may still simplify local constants in generated output. For debugging, the more reliable route is to debug through the source map in your original src/index.ts, or use unbundle/non-treeshaken dev builds. I would not expect a stable “preserve every local variable exactly as written” guarantee from the production pack output.

[snebjorn]

I tried both --sourcemap --no-treeshake --unbundle and config. But unfortunately the output is still

#!/usr/bin/env node
//#region src/index.ts
console.log(["hello", "world"].join(" "));
//#endregion
export {};

//# sourceMappingURL=index.mjs.map

Perhaps that's due to it being a single file.

the more reliable route is to debug through the source map in your original src/index.ts

Isn't that what the source maps does? I'm seeing this in the source map file "sources":["../src/index.ts"]

or use unbundle/non-treeshaken dev builds

Are you referring to --sourcemap --no-treeshake --unbundle here? Or is there another way?

---

Perhaps I should explain my setup a bit.
I have a cli package and I have some sample apps that use the cli. I want the sample apps to use the built output of my cli package so the tools, compilers, etc in the sample app doesn't go digging in the cli code for type or lint errors. However I still want breakpoint to be hit in my cli package when ran from one of the samples.

I have not be able to find a good setup that gives good DX.

[camc314]

Probably also want to set https://tsdown.dev/reference/api/Interface.UserConfig#minify

minify: false (I suspect oxc's minifier is inlining/collapsing the join here)

[snebjorn]

minify: false did the trick, thanks.

To summarize --sourcemap --no-treeshake --unbundle --no-minify works

[cookesan]

Glad minify: false closed the loop. Thanks for confirming the final flag set; that summary will help the next person trying to debug through bundled CLI output.