Use Math.abs for taxable amount in negative expense tax calculation

[MelvinBot]

Explanation of Change

When creating a negative expense (e.g., -$5.00) with taxes enabled, the tax amount was calculated using the raw negative transaction.amount, which produced a negative tax value. The confirmation page masked this by displaying the absolute value via getTaxAmount, but the negative value was sent to the backend which treated it as zero.

This change wraps the non-distance taxableAmount in Math.abs() so that calculateTaxAmount always receives a positive amount, producing the correct positive tax value that persists after expense creation.

Fixed Issues

$ #83087
PROPOSAL: #83087 (comment)

Tests

1. Enable taxes on a workspace
2. Go to the workspace chat
3. Click + > Create expense > Manual
4. Enter a negative amount (e.g., -$5.00) > Next
5. On the confirm page, click Tax field and select a non-zero tax rate (e.g., 5%)
6. Verify the tax amount is non-zero on the confirm page
7. Click Create expense
8. Open the created expense
9. Verify the tax amount is non-zero and matches the confirm page value

• Verify that no errors appear in the JS console

Offline tests

N/A — Tax calculation is performed client-side before the API call. Offline behavior is unchanged.

QA Steps

1. Enable taxes on a workspace
2. Go to the workspace chat
3. Click + > Create expense > Manual
4. Enter a negative amount (e.g., -$5.00) > Next
5. On the confirm page, click Tax field and select a non-zero tax rate (e.g., 5%)
6. Verify the tax amount is non-zero on the confirm page
7. Click Create expense
8. Open the created expense
9. Verify the tax amount is non-zero and matches the confirm page value

• 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 any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick)
  • 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 shown in the product is localized by adding it to src/languages/* files and using the translation method
    • If any non-english text was added/modified, I used JaimeGPT to get English > Spanish translation. I then posted it in #expensify-open-source and it was approved by an internal Expensify engineer. Link to Slack message:
  • I verified all numbers, amounts, dates and phone numbers shown in the product are using the localization methods
  • 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)
  • I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
  • I verified the JSDocs style guidelines (in STYLE.md) were followed
• 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)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.ts or at the top of the file that uses the constant) are defined as such
• I verified that if a function's arguments changed that all usages have also been updated correctly
• If any new file was added I verified that:
  • The file has a description of what it does and/or why is needed at the top of the file if the code is not self explanatory
• 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.
• If a new page is added, I verified it's using the ScrollView component to make it scrollable when more elements are added to the page.
• 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: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

[MelvinBot]

I created this PR from an upstream branch since I don't have push access to your fork.

To take ownership of this branch and be able to push updates, run:

git remote add upstream https://github.com/Expensify/App.git
git fetch upstream claude-fixNegativeExpenseTaxAmount
git checkout -b claude-fixNegativeExpenseTaxAmount upstream/claude-fixNegativeExpenseTaxAmount
git push -u origin claude-fixNegativeExpenseTaxAmount

Then you can close this PR and open a new one from your fork.

[MelvinBot]

The failing checks are unrelated to this PR's changes.

Failing checks: build (Debug, true) (Android) and build (Expensify Dev, Debug, true) (iOS) — both hybrid/Expensify builds.

Root cause: A Node engine version mismatch in the CI environment. The Mobile-Expensify submodule requires node 20.19.5, but the CI runner has node v20.20.0:

npm error notsup Required: {"node":"20.19.5","npm":"10.8.2"}
npm error notsup Actual:   {"npm":"10.8.2","node":"v20.20.0"}

This fails during the postInstall.sh script when installing node modules in the Mobile-Expensify submodule.

Evidence this is not PR-related:

• The non-hybrid builds (developmentDebug, false and DebugDevelopment, false) both passed
• The same failure is occurring on the main branch's iOS build (run 22468163260)
• This PR only changes one file (src/components/MoneyRequestConfirmationList.tsx) — a single Math.abs() wrapper — which has no connection to Node engine configuration

No code fix from this PR can resolve this. It's a CI infrastructure issue that needs the Node version pinned/updated in the CI runner or the engine constraint relaxed in Mobile-Expensify.

[MelvinBot]

The failing checks are unrelated to this PR's changes.

Failing checks: build (Debug, true) (Remote Build Android) and build (Expensify Dev, Debug, true) (Remote Build iOS)

Root cause: The Mobile-Expensify submodule's package.json requires node 20.19.5, but the App repo's .nvmrc specifies 20.20.0. Combined with engine-strict=true in .npmrc, the postInstall.sh script fails when running npm i inside the submodule because the node versions don't match.

Evidence this is unrelated:

• This PR only changes src/components/MoneyRequestConfirmationList.tsx
• The main branch has the exact same failure (EBADENGINE: Required node 20.19.5, Actual v20.20.0)
• The failure occurs in the "Setup Node" step during postInstall.sh, not in any code compilation or test step
• Only the HybridApp build variants (where IS_HYBRID_APP_REPO=true) are affected; standalone NewDot builds pass

The Mobile-Expensify submodule needs its engines.node updated to 20.20.0 to match the App repo.

[rojiphil]

@MelvinBot Code LGTM. Please mark the PR as "Ready for review"

[MelvinBot]

PR has been marked as Ready for review as requested. ✅

[melvin-bot]

@rojiphil Please copy/paste the Reviewer Checklist from here into a new comment on this PR and complete it. If you have the K2 extension, you can simply click: [this button]

[rojiphil]

Reviewer Checklist

• I have verified the author checklist is complete (all boxes are checked off).
• I verified the correct issue is linked in the ### Fixed Issues section above
• I verified testing steps are clear and they cover the changes made in this PR
  • I verified the steps for local testing are in the Tests section
  • I verified the steps for Staging and/or Production testing are in the QA steps section
  • I verified the steps cover any possible 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 checked that screenshots or videos are included for tests on all platforms
• I included screenshots or videos for tests on all platforms
• I verified that the composer does not automatically focus or open the keyboard on mobile unless explicitly intended. This includes checking that returning the app from the background does not unexpectedly open the keyboard.
• I verified tests pass on all platforms & I tested again on:
  • Android: HybridApp
  • Android: mWeb Chrome
  • iOS: HybridApp
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
• If there are any errors in the console that are unrelated to this PR, I either fixed them (preferred) or linked to where I reported them in Slack
• I verified there are no new alerts related to the canBeMissing param for useOnyx
• I verified proper code patterns were followed (see Reviewing the code)
  • I verified that any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick).
  • 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 shown in the product is localized by adding it to src/languages/* files and using the translation method
  • I verified all numbers, amounts, dates and phone numbers shown in the product are using the localization methods
  • 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)
  • I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
  • I verified the JSDocs style guidelines (in STYLE.md) were followed
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I verified that this PR follows the guidelines as stated in the Review Guidelines
• I verified other components that can be impacted by these changes have been tested, and I retested again (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar have been tested & I retested again)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.ts or at the top of the file that uses the constant) are defined as such
• If a new component is created I verified that:
  • A similar component doesn't exist in the codebase
  • All props are defined accurately and each prop has a /** comment above it */
  • The file is named correctly
  • The component has a clear name that is non-ambiguous and the purpose of the component can be inferred from the name alone
  • The only data being stored in the state is data necessary for rendering and nothing else
  • For Class Components, any internal methods passed to components event handlers are bound to this properly so there are no scoping issues (i.e. for onClick={this.submit} the method this.submit should be bound to this in the constructor)
  • Any internal methods bound to this are necessary to be bound (i.e. avoid this.submit = this.submit.bind(this); if this.submit is never passed to a component event handler like onClick)
  • All JSX used for rendering exists in the render method
  • The component has the minimum amount of code necessary for its purpose, and it is broken down into smaller components in order to separate concerns and functions
• If any new file was added I verified that:
  • The file has a description of what it does and/or why is needed at the top of the file if the code is not self explanatory
• 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 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.
• If a new page is added, I verified it's using the ScrollView component to make it scrollable when more elements are added to the page.
• For any bug fix or new feature in this PR, I verified that sufficient unit tests are included to prevent regressions in this 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.
• I have checked off every checkbox in the PR reviewer checklist, including those that don't apply to this PR.

Screenshots/Videos

Android: HybridApp

83643-android-hybrid-001.mp4

Android: mWeb Chrome

83643-mweb-chrome-001.mp4

iOS: HybridApp

83643-ios-hybrid-001.mp4

iOS: mWeb Safari

83643-mweb-safari-001.mp4

MacOS: Chrome / Safari

83643-web-chrome-001.mp4

[rojiphil]

@inimaga @trjExpensify Changes LGTM and works well too.
Approving for your review. Thanks.