The function inside the closure will be renamed

[zlargon]

Describe the bug

The internal function will be renamed if its name is same to the external function.
This seems related to the compiler because it won't happen when vite is working with pure javascript.

function myFunc() {
  return function myFunc() {};
}

// expect the function name to be 'myFunc', but the actual name is 'myFunc2'
console.log(myFunc().name);

Can be reproduced with:

Combination	Link
vite + typescript	https://stackblitz.com/edit/vitejs-vite-7fmv91?file=src/main.ts
vite + react	https://stackblitz.com/edit/vitejs-vite-w9neds?file=src/App.jsx
vite + typescript + react	https://stackblitz.com/edit/vitejs-vite-bdguti?file=src/App.tsx

Cannot be reproduced with:

Combination	Link
vite + javascript	https://stackblitz.com/edit/vitejs-vite-7rhr1u?file=main.js
pure typescript	https://stackblitz.com/edit/typescript-v3lbde?file=index.ts
create-react-app + javascript	None
create-react-app + typescript	None

Reproduction

https://stackblitz.com/edit/vitejs-vite-7fmv91?file=src/main.ts

Steps to reproduce

• npm install
• npm run dev

System Info

System:
  OS: Linux 5.0 undefined
  CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
  Memory: 0 Bytes / 0 Bytes
  Shell: 1.0 - /bin/jsh

Binaries:
  Node: 16.14.2 - /usr/local/bin/node
  Yarn: 1.22.19 - /usr/local/bin/yarn
  npm: 7.17.0 - /usr/local/bin/npm

npmPackages:
  vite: ^3.2.4 => 3.2.4

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[luo3house]

If run vite build in cases above, all the name of functions will be changed due to esbuild minify.

You may let esbuild keep the function name by Object.defineProperty(fn, "name", ...), and finally got the original name.

// vite.config.js
export default defineConfig({
  esbuild: {
    keepNames: true
  }
})

There is another esbuild REPL for reproduction.

[zlargon]

Ah, I see. Good to know that the function name will be changed by esbuild.

I try to add esbuild.keepNames in vite.config.js, but it doesn't work. Is something missing?

Not work

Combination	Link
vite + typescript	https://stackblitz.com/edit/vitejs-vite-7fmv91?file=vite.config.js
vite + react	https://stackblitz.com/edit/vitejs-vite-w9neds?file=vite.config.js
vite + typescript + react	https://stackblitz.com/edit/vitejs-vite-bdguti?file=vite.config.ts

Can work

It can work if I use Object.defineProperty without adding esbuild.keepNames in vite.config.js. However, I prefer the solution to config esbuild so that I don't need to refactor the huge code base.

function myFunc() {
  function myFunc() {}
  Object.defineProperty(myFunc, 'name', { value: 'myFunc' });
  return myFunc;
}

[luo3house]

You are right. esbuild keepNames option are still set to false by Vite though it is presented in user config.

There is an early issue(#9164). It discovered the keepNames breaks the tree-shaking.

[zlargon]

Got it. I think it would be better to update the document to mention some of the esbuild configs are disabled.
https://vitejs.dev/config/shared-options.html#esbuild

Does Vite has a plan to bring keepNames back in the future? I would like to keep tracking this if there is a relevant thread.

[lyleaigbedion]

+1 on this, vite renames a function in my app, breaking my feature completely. Is there an eta on when this will be re enabled?

[sapphi-red]

Duplicate of #13727