Bump webpack and remove event-target-shim

[compulim]

Fixes #5155.

Changelog Entry

Known issues

• Web Chat is not loading with error Uncaught TypeError: Super constructor null of anonymous class is not a constructor
  • A bug in webpack@>=5.84.1 is causing the issue. Please update to webpack@>=5.90.0

Fixed

• Fixes #5155. Fixed "Super constructor null of anonymous class is not a constructor" error in CDN bundle by bumping to webpack@5.91.0, in PR #5156, by @compulim

Changed

• Bumped all dependencies to the latest versions, by @compulim in PR #4973, PR #5115, PR #5148, and PR #5156
  • Development dependencies
    • webpack@5.91.0

Description

webpack@5.84.1 has a bug that marked event-target-shim to be "unused pure superclass". We are on webpack@5.89.0 and is experiencing the bug.

Our recent ESM work (#5148) emits minified code in our package tarball and expose the issue in Webpack. For example:

var ABC = class extends XYZ {}, abc = new ABC();

Webpack will re-emit it as following and marked the XYZ superclass as "unused pure":

var ABC = class extends (null && XYZ) {}, abc = new ABC();

Despite our E2E tests use CDN bundle, we did not catch this issue in PR validation because it will only repro on production build. In other words, it only repro on NODE_ENV=production npm run build.

Design

While we are working on the issue, we thought it was related to event-target-shim. Since we dropped IE11 support, we no longer need majority functionality of event-target-shim, we replaced it with our own createOnEventShim.

We continue to keep this replacement work as it will reduce our bundle size.

Specific Changes

• Bump to webpack@5.91.0
• Removed event-target-shim and replaced with createOnEventShim

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

Review Checklist

This section is for contributors to review your work.

• 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)