export createAttachmentMiddleware to reduce changes for custom middlewares provided by hosts

[bkebede252]

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Description

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• We were trying to create a custom attachmentmiddleware, it seems that if we copy the current code we'd miss out on future implementations. By exporting the createAttachmentmiddleware, we can wrap custom code on top of the default attachmentmiddleware. Here is a sample code :

import { createAttachmentMiddleware } from '@microsoft/omnichannel-chat-widget'

const customAttachmentMiddleware =
() =>
() =>
(next: any) =>
(...args: any) => {
// set custom code here to return custom component or logic before triggering default attachment middleware
const [card] = args
if (!card?.activity) {
return next(...args)
}

  const {
    activity: { attachments },
    attachment,
  }: { activity: { attachments: any }; attachment: any } = card
  // No attachment
  if (!attachments || !attachments.length || !attachment) {
    return next(...args)
  }

  // Check for Adaptive cards
  // eslint-disable-next-line prefer-const
  let { content, contentType } = attachment || { content: '', contentType: '' }
  let { type } = content || { type: '' }

  if (type === 'AdaptiveCard' || contentType === 'application/vnd.microsoft.card.adaptive') { 
    return <SampleComponent attachment={ attachment }/>
  }

  // end of custom code 
  // default attachment middleware from omnichannel-chat-widget
  return createAttachmentMiddleware(enableInlinePlaying)()(next)(...args)
}

Solution Proposed

Detail what is the solution proposed, include links to design document if required or any other document required to support the solution

• Export createAttachmentMiddleware

Acceptance criteria

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Test cases and evidence

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Sanity Tests

• You have tested all changes in Popout mode
• You have tested all changes in cross browsers i.e Edge, Chrome, Firefox, Safari and mobile devices(iOS and Android)
• Your changes are included in the CHANGELOG

A11y

• You have run the Automated Accessibility Check and have no reported issues

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[bkebede252]

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