[HOLD for payment 2023-10-05] [$500] [Distance] Some rates in the distance field have an excessive number of zeros added after the decimal point

[kbecciv]

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Action Performed:

1. Change the rate of a workspace to 1.283
2. Request money -> Distance
3. Fill start and finish point
4. Click next and select that workspace

Expected Result:

the rate in the Distance field should be 1.283

Actual Result:

the rate in the Distance field: 1.283000000000...

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: 1.3.66.3
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

Recording.4363.mp4

Expensify/Expensify Issue URL:
Issue reported by: @hichamcc
Slack conversation: https://expensify.slack.com/archives/C049HHMV9SM/p1693912703643649

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• samh-nl | Contributor | 26728259

[DylanDylann]

Proposal

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

[Distance] Some rates in the distance field have an excessive number of zeros added after the decimal point

What is the root cause of that problem?

The result of this calculation is wrong

App/src/libs/DistanceRequestUtils.js

Line 78 in 57b7606

const ratePerUnit = rate * 0.01;

This is a problem of javascript like this

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

Using decimal.js (this lib is used in package-lock.json) like this

const ratePerUnit = new Decimal(rate).dividedBy(100).toNumber()

What alternative solutions did you explore? (Optional)

We also can round ratePerUnit by using the toFixed method of js with the number of digits after the comma

    const ratePerUnit = (rate * 0.01).toFixed(3); // need to confirm the number of digits after the comma

[ahmedGaber93]

Proposal

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

[Distance] Some rates in the distance field have an excessive number of zeros added after the decimal point

What is the root cause of that problem?

This is the expected result in js when multiply point values see here for more details

console.log(0.1 + 0.2)         ->  will print 0.30000000000000004 not 0.3

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

We need to use ratePerUnit.toFixed(3) here

App/src/libs/DistanceRequestUtils.js

Lines 72 to 82 in 0e836df

	const getDistanceMerchant = (distanceInMeters, unit, rate, currency, translate) => {
	const convertedDistance = convertDistanceUnit(distanceInMeters, unit);
	const distanceUnit = unit === CONST.CUSTOM_UNITS.DISTANCE_UNIT_MILES ? translate('common.miles') : translate('common.kilometers');
	const singularDistanceUnit = unit === CONST.CUSTOM_UNITS.DISTANCE_UNIT_MILES ? translate('common.mile') : translate('common.kilometer');
	const roundedDistance = convertedDistance.toFixed(2);
	const unitString = roundedDistance === 1 ? singularDistanceUnit : distanceUnit;
	const ratePerUnit = rate * 0.01;
	const currencySymbol = CurrencyUtils.getCurrencySymbol(currency) || `${currency} `;
	return `${roundedDistance} ${unitString} @ ${currencySymbol}${ratePerUnit} / ${singularDistanceUnit}`;
	};

What alternative solutions did you explore? (Optional)

we can use third party library like js-big-decimal.js or decimal.js

[namhihi237]

Proposal

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

Error displaying rate when requesting money

What is the root cause of that problem?

We use the function getDistanceMerchant to get distance merchant

App/src/libs/DistanceRequestUtils.js

Lines 72 to 82 in b11bddc

	const getDistanceMerchant = (distanceInMeters, unit, rate, currency, translate) => {
	const convertedDistance = convertDistanceUnit(distanceInMeters, unit);
	const distanceUnit = unit === CONST.CUSTOM_UNITS.DISTANCE_UNIT_MILES ? translate('common.miles') : translate('common.kilometers');
	const singularDistanceUnit = unit === CONST.CUSTOM_UNITS.DISTANCE_UNIT_MILES ? translate('common.mile') : translate('common.kilometer');
	const roundedDistance = convertedDistance.toFixed(2);
	const unitString = roundedDistance === 1 ? singularDistanceUnit : distanceUnit;
	const ratePerUnit = rate * 0.01;
	const currencySymbol = CurrencyUtils.getCurrencySymbol(currency) || `${currency} `;
	return `${roundedDistance} ${unitString} @ ${currencySymbol}${ratePerUnit} / ${singularDistanceUnit}`;
	};

The problem with this line

App/src/libs/DistanceRequestUtils.js

Line 78 in b11bddc

const ratePerUnit = rate * 0.01;

When performing the calculation 128.3 * 0.01 in JavaScript, the returned result is not 1.283, but 1.2830000000000001. This comes from the way computers handle decimals in the floating-point system.

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

To control the number of decimal places after the decimal point:

const ratePerUnit = (rate * 0.01).toFixed(3);

What alternative solutions did you explore? (Optional)

If we want to remove unnecessary zeros after the decimal point:

const ratePerUnit = Number((rate * 0.01).toFixed(3));

Or

const ratePerUnit = Number((rate * 0.01));

[samh-nl]

Proposal

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

Some rates in the distance field have an excessive number of zeros added after the decimal point

What is the root cause of that problem?

In DistanceRequestUtils.getDistanceMerchant, we multiply the value by 0.01, causing the extra decimals due to it being a floating point:

App/src/libs/DistanceRequestUtils.js

Line 78 in b11bddc

const ratePerUnit = rate * 0.01;

In other instances where the rate is displayed, we use getRateDisplayValue and getNumericValue to get the rate and use toFixed(3) to prevent this problem:

App/src/pages/workspace/reimburse/WorkspaceReimburseView.js

Line 80 in b11bddc

return numValue.toFixed(3);

App/src/pages/workspace/reimburse/WorkspaceRateAndUnitPage.js

Line 62 in b11bddc

return numValue.toFixed(3);

Furthermore, there are other inconsistencies. For example, here we multiply by 0.01, but in the other implementations we divide by CONST.POLICY.CUSTOM_UNIT_RATE_BASE_OFFSET (value of 100).

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

We currently have 3 implementations for getting the rate value, with getRateDisplayValue (and getNumericValue) being essentially duplicated in the two files mentioned above.

We should move getRateDisplayValue to a util file and use the same function everwhere (i.e. DistanceRequestUtils, WorkspaceRateAndUnitPage and WorkspaceRateAndUnitPage).

This would solve the issue and also make the implementations consistent.

Fixed result:

What alternative solutions did you explore? (Optional)

Option 1. Add toFixed(3), but this would be a less elegant approach.
Option 2. Use a library such as decimal.js for all money-related amounts.

[melvin-bot]

Job added to Upwork: https://www.upwork.com/jobs/~010a1acc02586756aa

[melvin-bot]

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

[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 @strepanier03 (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 - @burczu (External)

[trjExpensify]

@hayata-suenaga putting this one on your radar and adding it to the project board!

[burczu]

Reviewed all the proposals and all of them are correct in my opinion - I personally prefer just using the toFixed method here. @DylanDylann's proposal was first, so I think we should choose it.
But he proposed using library as a main solution and using toFixed as optional one. I'm not sure if it does matter in terms of choosing proposal - if it does, then the first proposal to choose is the one from @ahmedGaber93.

🎀 👀 🎀 C+ reviewed

[melvin-bot]

Triggered auto assignment to @luacmartins, see https://stackoverflow.com/c/expensify/questions/7972 for more details.

[samh-nl]

@burczu In both WorkspaceRateAndUnitPage and WorkspaceReimburseView we use the getRateDisplayValue function which does not have this issue. For consistency, why not apply the same method everywhere (rather than duplicating code)?

There's also another difference in implementation: * 0.01 (hard-coded value) is done here instead of dividing by 100 (CONST.POLICY.CUSTOM_UNIT_RATE_BASE_OFFSET) that is done in getRateDisplayValue, which seems like the intended way of displaying the rate.

[DylanDylann]

@samh-nl I see that it is the same idea using toFixed method to avoid this issue

[luacmartins]

hmm I think using getRateDisplayValue might be a better solution in this case. It seems like we already use that method in a few places, so maybe we should extract it into its own util method too. What do you think @burczu?

[burczu]

@luacmartins Yes, I agree.

[luacmartins]

In that case it seems like we should go with @samh-nl's proposal.

[melvin-bot]

📣 @hichamcc We're missing your Upwork ID to automatically send you an offer for the Reporter role.
Once you apply to the Upwork job, your Upwork ID will be stored and you will be automatically hired for future jobs!

[luacmartins]

Assigned @samh-nl to the issue

[samh-nl]

PR is ready for review: #27816

[melvin-bot]

Based on my calculations, the pull request did not get merged within 3 working days of assignment. Please, check out my computations here:

• when @samh-nl got assigned: 2023-09-18 08:43:47 Z
• when the PR got merged: 2023-09-25 02:55:47 UTC
• days elapsed: 4

On to the next one 🚀

[melvin-bot]

Reviewing label has been removed, please complete the "BugZero Checklist".

[melvin-bot]

The solution for this issue has been 🚀 deployed to production 🚀 in version 1.3.74-3 and is now subject to a 7-day regression period 📆. Here is the list of pull requests that resolve this issue:

• fix: use common function to display rate #27816

If no regressions arise, payment will be issued on 2023-10-05. 🎊

After the hold period is over and BZ checklist items are completed, please complete any of the applicable payments for this issue, and check them off once done.

• External issue reporter
• Contributor that fixed the issue
• Contributor+ that helped on the issue and/or PR

For reference, here are some details about the assignees on this issue:

• @burczu does not require payment (Contractor)
• @samh-nl requires payment offer (Contributor)
• @hichamcc requires payment

As a reminder, here are the bonuses/penalties that should be applied for any External issue:

• Merged PR within 3 business days of assignment - 50% bonus
• Merged PR more than 9 business days after assignment - 50% penalty

[melvin-bot]

BugZero Checklist: The PR fixing this issue has been merged! The following checklist (instructions) will need to be completed before the issue can be closed:

• [@burczu] The PR that introduced the bug has been identified. Link to the PR:
• [@burczu] The offending PR has been commented on, pointing out the bug it caused and why, so the author and reviewers can learn from the mistake. Link to comment:
• [@burczu] A discussion in #expensify-bugs has been started about whether any other steps should be taken (e.g. updating the PR review checklist) in order to catch this type of bug sooner. Link to discussion:
• [@burczu] Determine if we should create a regression test for this bug.
• [@burczu] If we decide to create a regression test for the bug, please propose the regression test steps to ensure the same bug will not reach production again.
• [@trjExpensify] Link the GH issue for creating/updating the regression test once above steps have been agreed upon:

[trjExpensify]

👋 @burczu can you complete the checklist please so we can proceed with payments? Thanks!

[melvin-bot]

@burczu, @trjExpensify, @luacmartins, @samh-nl Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

[trjExpensify]

Same, awaiting the checklist.

[burczu]

BugZero Checklist: The PR fixing this issue has been merged! The following checklist (instructions) will need to be completed before the issue can be closed:

• [@burczu] The PR that introduced the bug has been identified. Link to the PR: Modify MoneyRequestConfirmPage for Distance Request #25707
• [@burczu] The offending PR has been commented on, pointing out the bug it caused and why, so the author and reviewers can learn from the mistake. Link to comment: Modify MoneyRequestConfirmPage for Distance Request #25707 (comment)
• [@burczu] A discussion in #expensify-bugs has been started about whether any other steps should be taken (e.g. updating the PR review checklist) in order to catch this type of bug sooner. Link to discussion: Didn't find any
• [@burczu] Determine if we should create a regression test for this bug.
• [@burczu] If we decide to create a regression test for the bug, please propose the regression test steps to ensure the same bug will not reach production again.
• [@trjExpensify] Link the GH issue for creating/updating the regression test once above steps have been agreed upon: Don't think we need this as the default rate is three decimals for a workspace, so it will reveal itself in the standard creation flow.

[trjExpensify]

Okay, confirming payments on this one as follows:

• $50 to @hichamcc for the bug report
• $500 to @samh-nl for the bug fix

Sent offers! Once confirmed, I'll pay them out.

[hichamcc]

@trjExpensify accepted

[trjExpensify]

settled up with you both. Closing!