[Due for payment 2025-12-30] [Splits in NewDot] Add 'Split by date' to the split expense table for new splits

[garrettmknight]

Follow up to Expense Splitting in NewDot

[Figma]
[Predesign]

Feature Description

Implement a ‘Split by date’ flow that does the following:

1. Adds a third split options at the top of the split table: Amount, Percentage, (these should already exist) and Date (this is the new one)
2. When the user taps 'Date' in the split menu we'll change the view of the split table like so:

• Add a date picker for Start Date in the UI
• Add a date picker for End Date in the UI
• When the user confirms the dates, use the selected dates to overrwrite the existing splits in the table, creating one split for each day of the date range selected.
• Set the amounts of the individual splits to equal proportions of the original expense amount.

Important Notes:

• We'll maintain the logic and copy for our current warnings/errors on saving splits where the sum of the splits differs from the original transaction amounts.
• The 'Date' mode button will not be available when editing splits to avoid adding more logic to start

Enabling Date Mode

1. User taps More > Split
2. User taps the Date pill

Setting Dates and Generating Splits

1. User taps Split dates
2. Date picker for start date launches
3. User taps the preferred start date + Save
4. Date picker for the end date launches
5. User taps the preferred end date + Save
6. User taps Save to confirm their dates
7. We generate a split per day, setting the amounts equally for all splits, adding to the original transaction amount

Editing Dates and Regenerating Splits

1. User taps Split dates field, with current dates and number of days shown.
2. Split dates page shows, no date picker launches automatically
3. User taps End date
4. User taps the preferred end date + Save
5. User taps Save to confirm their dates
6. We clear the existing splits and generate a split per day for the updated dates, setting the amounts equally for all splits, adding to the original transaction amount

Manual Test Steps

Enabling Date Mode:

1. Submitter creates an expense for $200.
2. Submitter taps 'Split' from the 'More' menu. Two even splits are created in the Split table, each for $100.
3. Submitter taps the 'Date' pill

• Verify the pill is selected and the Split dates field shows

Changing Dates:

1. After step 3 above, tap on Split dates

• Verify that the Split dates page opens
• Verify that the date picker opens to the month the original transaction date is in

2. Set the start date as the 16th

• Verify that the date picker opens to the month the original transaction date is in

3. Tap Save

• Verify that the date picker opens to the month the original transaction date is in again for the end date

4. Set the end date as the 18th and tap Save
5. Tap Save in the Split dates page

• Verify three splits are created with equal amounts adding up to the original transaction amount

Automated Tests

Issue Owner

Current Issue Owner: @garrettmknight

[melvin-bot]

Current assignee @garrettmknight is eligible for the NewFeature assigner, not assigning anyone new.

[melvin-bot]

⚠️ It looks like this issue is labelled as a New Feature but not tied to any GitHub Project. Keep in mind that all new features should be tied to GitHub Projects in order to properly track external CAP software time ⚠️

[melvin-bot]

Triggered auto assignment to Design team member for new feature review - @dannymcclain (NewFeature)

[garrettmknight]

Assigning @dubielzyk-expensify since he's been working on this with me.

[garrettmknight]

This is queued for after Split evenly.