Add localTimestamp and localTimezone

[compulim]

Fixes #3788.

Changelog Entry

Added

• Resolved #3788. Added localTimestamp and localTimezone (if available) to all outgoing activities, by @compulim, in PR #3896

Description

For all outgoing activities, add localTimestamp and localTimezone (if supported by the browser settings).

Design

Although we send localTimestamp, Azure Bot Services will rename it to rawLocalTimestamp. The localTimestamp field is same as timestamp field, which is in UTC.

Original activity from Web Chat (captured from network trace)

  {
    "channelData": {
      "clientActivityID": "1621475335684ql44o56fi4",
      "clientTimestamp": "2021-05-20T01:48:55.684Z"
    },
    "text": "dump-activity",
    "textFormat": "plain",
    "type": "message",
    "channelId": "webchat",
    "from": {
      "id": "dl_3fc4640be134b83b9b3f71c853ffba4a",
      "name": "",
      "role": "user"
    },
    "locale": "en-US",
+   "localTimestamp": "2021-05-20T10:48:55.684+09:00",
+   "localTimezone": "Asia/Tokyo",
    "timestamp": "2021-05-20T01:48:55.684Z",
    "entities": [
      {
        "requiresBotState": true,
        "supportsListening": true,
        "supportsTts": true,
        "type": "ClientCapabilities"
      }
    ]
  }

Activity perceived on bot side

  {
    "type": "message",
    "id": "IXiRn3wwW8lI2WShb0KaXA-o|0000000",
    "timestamp": "2021-05-20T01:48:55.506Z",
+   "localTimestamp": "2021-05-20T01:48:55.684Z",
+   "localTimezone": "Asia/Tokyo",
    "serviceUrl": "https://directline.botframework.com/",
    "channelId": "directline",
    "from": {
      "id": "dl_3fc4640be134b83b9b3f71c853ffba4a",
      "name": ""
    },
    "conversation": {
      "id": "IXiRn3wwW8lI2WShb0KaXA-o"
    },
    "recipient": {
      "id": "webchat-mockbot@WYDIyKwAZCw",
      "name": "webchat-mockbot"
    },
    "textFormat": "plain",
    "locale": "en-US",
    "text": "dump-activity",
    "entities": [
      {
        "type": "ClientCapabilities",
        "requiresBotState": true,
        "supportsListening": true,
        "supportsTts": true
      }
    ],
    "channelData": {
      "clientActivityID": "1621475335684ql44o56fi4",
      "clientTimestamp": "2021-05-20T01:48:55.684Z"
    },
    "rawTimestamp": "2021-05-20T01:48:55.5067653Z",
+   "rawLocalTimestamp": "2021-05-20T10:48:55.684+09:00",
    "callerId": "urn:botframework:azure"
  }

Some environments don't support window.Intl

Some browsers in some settings, such as IE11 InPrivate mode, will return undefined for window.Intl.

Specific Changes

• Updated postActivitySaga to fill localTimestamp and optionally, localTimezone
• Added dateToLocaleISOString to create a local timestamp in ISO format
• In test harness, set browser to use UTC by default (to reuse the box after last test)

• 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)