[WIP] fix: preserve Markdown formatting in long messages

[Uzaifm127]

Explanation of Change

ExpensiMark.replace() was optimized to avoid running the autolink, bold, and strikethrough regexes over the complete text on every change. The scanner first finds small possible URL and Markdown candidates, then the existing ExpensiMark regexes validate and replace only those candidates.

This keeps the existing parsing behavior while reducing the work required for long composer messages.

react-native-live-markdown now allows parseExpensiMark function callers to provide the maximum length passed to parseExpensiMark.

App uses CONST.MAX_MARKUP_LENGTH, which is 10,000 characters. This PR passes that value to all the locations in the App that use parseExpensiMark for composer Markdown parsing and selected-text formatting, instead of using the library default of 4,000.

Fixed Issues

$ #95210
PROPOSAL: #95210 (comment)

Tests

Note

The complete composer text, including the Markdown added during testing, must contain more than 4,000 and fewer than 10,000 characters.

Test 1 (All platforms)

Note

Android native has a separate known typing-delay issue with long text, which will be handled in a follow-up. Do not fail this PR because of that delay. For Android native, verify that Markdown remains preserved after 4,000 characters. On the other platforms, also verify that typing remains responsive.

1. Go to staging.new.expensify.com or open Expensify App
2. Login with any account
3. Go to any chat
4. Paste any long text (4000+ characters) containing markdown (bold, italic, strikethrough and autolink).
5. Try to write something after pasting.
6. Verify that the typing experience is smooth and it doesn't lag or freezes while typing.
7. Verify that the markdown is preserved when we type after pasting 4000+ characters text in the composer.

Test 2 (Web)

1. Open https://staging.new.expensify.com/
2. Go to any chat.
3. Paste the long text more than 4000 characters in the composer containing bold and italic (the long text must include bold and italic markdown formatting).
4. Select only bold, without selecting the stars (*).
5. Press Cmd+B on macOS or Ctrl+B on Windows
6. Verify that the surrounding stars are removed and the text becomes plain.
7. Select italic, without underscores.
8. Press Cmd+I or Ctrl+I.
9. Verify that the underscores are removed and the text become plain.
10. Select the plain text again and repeat the shortcuts.
11. Verify that the plain text becomes bold on pressing cmd/ctrl + b and becomes italic on pressing cmd/ctrl + i.

Test 3 (All platforms)

1. Open any chat.
2. Paste plain text containing more than 4,000 characters, while keeping the complete composer text under 10,000 characters.
3. On a new line, paste `😄` without selecting any existing text.
4. Verify that the emoji inside the backticks is converted to `:smile:`.
5. On another new line, paste :smile: and `:wave:` without selecting any existing text.
6. Verify that :smile: outside the backticks becomes 😄.
7. Verify that :wave: inside the backticks remains unchanged.

Test 4 (All platforms)

1. Open any chat.
2. Paste plain text containing more than 4,000 characters, while keeping the complete composer text under 10,000 characters.
3. On a new line, type two backticks.
4. Place the cursor between the backticks and type :smi, for example: `:smi`.
5. Verify that emoji suggestions do not appear because the cursor is inside a complete code range.
6. Type :smi outside the backticks.
7. Verify that emoji suggestions appear outside the code range.

• Verify that no errors appear in the JS console

Offline tests

Same as Test

QA Steps

Same as Test

• Verify that no errors appear in the JS console

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I followed proper code patterns (see Reviewing the code)
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I followed the guidelines as stated in the Review Guidelines
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• If a new CSS style is added I verified that:
  • A similar style doesn't already exist
  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))
• If new assets were added or existing ones were modified, I verified that:
  • The assets are optimized and compressed (for SVG files, run npm run compress-svg)
  • The assets load correctly across all supported platforms.
• If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
• If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
  • I verified that all the inputs inside a form are aligned with each other.
  • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Android-native.mov

Android: mWeb Chrome

android.mweb.mp4

iOS: Native

ios-native.mp4

iOS: mWeb Safari

ios-safari.mp4

MacOS: Chrome / Safari

macOS.web.mp4

[github-actions]

⚠️ This PR is possibly changing native code and/or updating libraries, it may cause problems with HybridApp. Please check if any patch updates are required in the HybridApp repo and run an AdHoc build to verify that HybridApp will not break. Ask Contributor Plus for help if you are not sure how to handle this. ⚠️

[codecov]

Codecov Report

❌ Looks like you've decreased code coverage for some files. Please write tests to increase, or at least maintain, the existing level of code coverage. See our documentation here for how to interpret this table.

Files with missing lines	Coverage Δ
src/libs/EmojiUtils.tsx	85.64% <100.00%> (-0.35%)	⬇️
src/libs/FormatSelectionUtils.ts	100.00% <100.00%> (ø)
src/libs/ParsingUtils.ts	89.74% <100.00%> (+7.69%)	⬆️
... and 69 files with indirect coverage changes