Build: add entry points without top level side-effects

[OEvgeny]

Fixes #

Changelog Entry

Changed

• Excluded side effects from module entry points to prevent global scope modification, in PR #5329, by @OEvgeny

Description

This PR improves the bundle architecture by migrating from Webpack to tsup and restructuring entry points to eliminate top-level side effects.

Design

The solution implements a cleaner separation between bundle and module code:

1. /module/exports*.ts - Pure ES/CJS modules without side effects

   • Export Web Chat API surface
   • Maintain module-level encapsulation
   • Enable tree-shaking optimizations

2. /bundle/index*.ts - Bundle entry points with controlled side effects

   • Handle global window.WebChat registration
   • Manage version metadata
   • Import and expose module exports

This approach:

• Separates concerns between module API and bundle initialization
• Improves predictability of side effects
• Makes the codebase more maintainable
• Enables better tree-shaking in downstream applications

Specific Changes

• Migrated build system from Webpack to tsup
• Restructured bundle package layout:
  • Added src/module/exports.ts, exports-es5.ts, exports-minimal.ts
  • Added src/bundle/index.ts, index-es5.ts, index-minimal.ts
  • Moved polyfill.ts to src/bundle
• Updated package.json:
  • Removed Webpack-related dependencies
  • Updated build scripts to use tsup
• Improved type definitions
• Added React resolution through isomorphic-react

-

• I have added tests and executed them locally
• I have updated CHANGELOG.md
• I have updated documentation

Review Checklist

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)

[compulim]

I like that we don't need to export global in a way that we dupe export as modules.