Clean up middleware signature

[compulim]

Changelog Entry

Breaking changes

• The following middleware should be created using their respective factory functions:
  • activityBorderDecoratorMiddleware, related to PR #5504
  • activityGroupingDecoratorMiddleware, related to PR #5504
  • sendBoxMiddleware, related to PR #5504
  • sendBoxToolbarMiddleware, related to PR #5504

Added

• Added sendBoxMiddleware and sendBoxToolbarMiddleware, by @compulim, in PR #5120 and #5504
  • Instead of passing barebone middleware, use the createSendBoxMiddleware and createSendBoxToolbarMiddleware correspondingly, related to PR #5504

Description

Clean up middleware signature to prepare for poly-middleware.

Eventually, we will unite all middleware signature to the following format.

const someMiddleware: Middleware<Request, Props> = 
  (init: string) => 
    (next: Enhancer<Request>) => 
      (request: Request) =>
        next(request) satisfies ComponentType<Props>;

Design

Introduction of createXXXMiddleware

Narrowing and guarding function overloading is still weak in TypeScript. Until they improve it, we need a "wrapping function" to make middleware typed properly.

We cannot do use first argument to differentiate the type of return value.

interface SomeFunction {
  (type: 'n'): number;
  (type: 's'): string;
}

We will also leverage the createXXXMiddleware for backward/forward compatibility.

Specific Changes

• Cleaned up decorator middleware typing
  • Removed unnecessary typing and their exports
  • init will always be a string, only Request and Props are customizable
  • Added new createActivityBorderMiddleware(), createActivityGroupingMiddleware(), createSendBoxMiddleware() and createSendBoxToolbarMiddleware() helper functions to wrap their decorator middleware correspondingly
• Updated templateMiddleware
  • New typing helper Infer*<typeof template> to infer from template['~types']

• 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)