Fix double .js extension in build output

[myabc]

This PR fixes the issue where the build was generating index.js.js instead of index.js.

Changes

• Changed fileName from 'index.js' to 'index' in vite.config.ts
• Added entryFileNames: 'index.js' to rollup output options to ensure correct output filename

Problem

The npm package was including index.js.js in the dist folder, causing import resolution failures with esbuild and other bundlers.

Solution

Vite/Rollup automatically adds the appropriate extension based on the format, so we shouldn't include .js in the fileName. The entryFileNames option ensures the final output is exactly index.js.

Closes #24

[knowledgecode]

Thank you so much for identifying and fixing this issue! 🙏

I wasn't aware of this problem because my application bundler (Vite) was resolving the incorrect filename automatically.

I've reviewed and tested your changes - the fix works perfectly! I'm happy to merge this PR.

One small note: Based on my testing, the entryFileNames: 'index.js' addition might not be necessary. Vite's lib.fileName option alone (without the .js extension) appears to generate the correct index.js output file. The rollupOptions.output.entryFileNames seems to override lib.fileName, which could potentially cause confusion in the future.

However, your solution works correctly and I really appreciate your contribution. I'll merge this as-is, and I may clean up the potentially redundant entryFileNames configuration in a follow-up commit.

Thanks again for taking the time to fix this and submit the PR! 🎉