[HOLD for payment 2023-10-09] [$500] Web - Pasting emojis freezes cursor position in composer box (works fine in edit message)

[kbecciv]

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Action Performed:

1. Open the app
2. Open any report
3. React to any message with any emoji
4. Right click on reaction and copy the emoji text
5. Paste the copied emoji text few times in compose box and observe that cursor is freezes after first pasted emoji
6. Try to paste similarly in edit message and observe that it works fine

Expected Result:

App should move cursor to end on pasting the emojis in compose box as it does in edit message box

Actual Result:

App freezes cursor after first pasted emoji in compose box

Workaround:

Unknown

Platforms:

Which of our officially supported platforms is this issue occurring on?

• Android / native
• Android / Chrome
• iOS / native
• iOS / Safari
• MacOS / Chrome / Safari
• MacOS / Desktop

Version Number: 1.3.71.4
Reproducible in staging?: y
Reproducible in production?: y
If this was caught during regression testing, add the test name, ID and link from TestRail:
Email or phone of affected tester (no customers):
Logs: https://stackoverflow.com/c/expensify/questions/4856
Notes/Photos/Videos: Any additional supporting documentation

pasting.emoji.in.composer.freezes.the.cursor.position.mp4

Recording.4556.mp4

Expensify/Expensify Issue URL:
Issue reported by: @dhanashree-sawant
Slack conversation: https://expensify.slack.com/archives/C049HHMV9SM/p1694883795401949

View all open jobs on GitHub

Upwork Automation - Do Not Edit

• Upwork Job URL: https://www.upwork.com/jobs/~0141004fff370e0c4e
• Upwork Job ID: 1703759230392123392
• Last Price Increase: 2023-09-25
• Automatic offers:
• Ollyws | Reviewer | 26897303
• jeet-dhandha | Contributor | 26897305
• dhanashree-sawant | Reporter | 26897308

[ahmedGaber93]

Proposal

Please re-state the problem that we are trying to solve in this issue.

Pasting emojis freezes cursor position in composer box (works fine in edit message)

What is the root cause of that problem?

wrong calculation by getCommonSuffixLength here

App/src/pages/home/report/ReportActionCompose/ComposerWithSuggestions.js

Line 188 in c77814f

const remainder = ComposerUtils.getCommonSuffixLength(commentRef.current, newComment);

App/src/libs/ComposerUtils/index.js

Lines 37 to 43 in c77814f

	function getCommonSuffixLength(str1, str2) {
	let i = 0;
	while (str1[str1.length - 1 - i] === str2[str2.length - 1 - i]) {
	i++;
	}
	return i;
	}

how getCommonSuffixLength work? see this example

const reminder = getCommonSuffixLength("START :joy END", "START 😂 END"); // CommonSuffix is ` END` and length 4.  
const newSelection  = "START 😂 END".length - reminder; // result 12 - 4 = 8
// cursor position 8 is true and set after the emoji

Why it failed in this case.
because when matching the CommonSuffix the replaced emoji joy 😂 is match the previous of it, so it not stop on it

// note "😂 ".length is 3
const reminder = getCommonSuffixLength("😂 ", "😂 😂 "); // resul 3
const newSelection  = "😂 😂 ".length - reminder; // result 6 - 3 = 3
const reminder = getCommonSuffixLength("😂 😂 ", "😂 😂 😂 "); // resul 6
const newSelection  = "😂 😂 😂 ".length - reminder; // result 9 - 6 = 3
const reminder = getCommonSuffixLength("😂 😂 😂 ", "😂 😂 😂 😂 "); // resul 9
const newSelection  = "😂 😂 😂 😂 ".length - reminder; // result 12 - 9 = 3

whatever we type the newSelection is 3.

// CommonSuffix between `😂 😂 cursor here 😂` and  `😂 😂 😂 😂 ` should be only `😂 `
// but becaue the replace emoji match the previous of it, CommonSuffix wii be 😂 😂 😂

What changes do you think we should make in order to solve the problem?

Reverse the way we used to get the new position.
Old way comment.length - CommonSuffix.length "START 😂 END" - " END"
new way CommonPrefix + emoji.length + space.length "START" + 😂 + " "

What is the different in the new way?

when we use CommonPrefix we will stop in the current cursor position, so if the replaced emoji match the next of it, it not affect because we will stop in the current cursor position

// add this new method on ComposerUtils
function getCommonPrefixLength(str1, str2, end) {
    let i = 0;
    while (str1[i] === str2[i] && i < end) { // start from i not length - 1 - i and i < end will do the disired fix.
        i++;
    }
    return i;
}

and the emoji length and newSelectionPosition length

if (commentValue !== newComment) {
    const remainder = ComposerUtils.getCommonPrefixLength(commentRef.current, newComment, selection.end);
    const emojiLength = newComment.substring(remainder).match(CONST.REGEX.EMOJIS)[0].length;
    const spaceAfterEmojiLength = 1;
    const newSelectionPosition = remainder + emojiLength + spaceAfterEmojiLength;
    setSelection({
        start: newSelectionPosition,
        end: newSelectionPosition,
    });
}

we need to add selection.end in callback deps

result

Screen.Recording.2023-09-18.at.1.34.22.AM.mov

What alternative solutions did you explore? (Optional)

N/A

[melvin-bot]

Triggered auto assignment to @lschurr (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details.

[melvin-bot]

Job added to Upwork: https://www.upwork.com/jobs/~0141004fff370e0c4e

[melvin-bot]

Bug0 Triage Checklist (Main S/O)

• This "bug" occurs on a supported platform (ensure Platforms in OP are ✅)
• This bug is not a duplicate report (check E/App issues and #expensify-bugs)
  • If it is, comment with a link to the original report, close the issue and add any novel details to the original issue instead
• This bug is reproducible using the reproduction steps in the OP. S/O
  • If the reproduction steps are clear and you're unable to reproduce the bug, check with the reporter and QA first, then close the issue.
  • If the reproduction steps aren't clear and you determine the correct steps, please update the OP.
• This issue is filled out as thoroughly and clearly as possible
  • Pay special attention to the title, results, platforms where the bug occurs, and if the bug happens on staging/production.
• I have reviewed and subscribed to the linked Slack conversation to ensure Slack/Github stay in sync

[melvin-bot]

Triggered auto assignment to @Christinadobrzyn (External), see https://stackoverflow.com/c/expensify/questions/8582 for more details.

[melvin-bot]

Triggered auto assignment to Contributor-plus team member for initial proposal review - @Ollyws (External)

[jeet-dhandha]

Proposal

Please re-state the problem that we are trying to solve in this issue.

• Cursor staying after the first emoji in the text input when continuosly pasting ":joy:".

What is the root cause of that problem?

• Cursor position is not being as we are comparing wrong values. commentRef.current & newComment

App/src/pages/home/report/ReportActionCompose/ComposerWithSuggestions.js

Line 188 in 9b302c9

const remainder = ComposerUtils.getCommonSuffixLength(commentRef.current, newComment);

• I am still not sure why we are comparing commentRef.current with newComment instead of commentValue.

• As in below example newComment will always be different then commentValue as :joy: text will parsed to emoji.

const commentValue = ":joy:";
const newComment = " 😂 "; // After parsing

const isEqual = commentValue === newComment; // false

What changes do you think we should make in order to solve the problem?

• We should compare the newComment with the commentValue instead of commentRef.current.

What alternative solutions did you explore? (Optional)

• N/A