Break up src/libs/actions/IOU.ts

[roryabraham]

HOLD for #66507

Problem

src/libs/actions/IOU.ts is so large (nearly 14k lines!) that git blame and GitHub syntax highlighting don't work in it, making it difficult to review or search history in.

Solution

Time to break up the party! Let's break it up into smaller distinct pieces.

Issue Owner

Current Issue Owner: @greg-schroeder

[roryabraham]

@parasharrajat is going to take point on this initiative

[melvin-bot]

Triggered auto assignment to @greg-schroeder (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details. Please add this bug to a GH project, as outlined in the SO.

[lorretheboy]

Proposal

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

src/libs/actions/IOU.ts is so large (nearly 14k lines!) that git blame and GitHub syntax highlighting don't work in it, making it difficult to review or search history in.

What is the root cause of that problem?

Refactoring

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

Split IOU.ts into focused, domain-specific modules based on functional boundaries:

1. Transaction operations - Create, update, delete, and manage individual transactions
2. Money request operations - Request money, track money, split bills
3. Receipt handling - Upload, scan, replace, and process receipts
4. Distance tracking - Distance-based expense creation and waypoint management
5. Report operations - Submit, approve, pay, and manage expense reports
6. Optimistic data builders - Helper functions that build optimistic Onyx data structures
7. Shared utilities - Common validation, formatting, and helper functions
   ...etc

Each module would:

• Export only its public API functions
• Keep internal helpers private
• Maintain existing function signatures to avoid breaking changes
• Import from other modules as needed
• Be placed in src/libs/actions/IOU/ directory

The main IOU.ts would become a thin re-export layer that maintains backward compatibility by importing and re-exporting all functions from the new modules, allowing existing imports throughout the codebase to continue working without modification.

What alternative solutions did you explore? (Optional)

Reminder: Please use plain English, be brief and avoid jargon. Feel free to use images, charts or pseudo-code if necessary. Do not post large multi-line diffs or write walls of text. Do not create PRs unless you have been hired for this job.

[mohammadjafarinejad]

Proposal

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

• src/libs/actions/IOU.ts is so large (nearly 14k lines!) that git blame and GitHub syntax highlighting don't work in it, making it difficult to review or search history in.

What is the root cause of that problem?

• Refactoring.

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

We should split IOU.ts into smaller files by business domain to improve readability, reviewability, and maintainability while keeping related logic together. The file currently has 136 public functions that can be grouped into clear areas like money requests, distance requests, split bills, and expense tracking, etc..

Suggested structure:

I tried to organize as many functions as possible, but there are a few more that I didn’t include. Still, I think this structure gives us a solid starting point. We can adjust it more in the PR.

• /IOU/moneyRequest.ts (25 functions, ~1500 lines)
  Core money request operations including creation, editing, updating fields, and deletion.

  Functions

  • createDraftTransaction()
  • startMoneyRequest()
  • requestMoney()
  • getMoneyRequestInformation()
  • setMoneyRequestAmount()
  • setMoneyRequestCreated()
  • setMoneyRequestCurrency()
  • setMoneyRequestDescription()
  • setMoneyRequestMerchant()
  • setMoneyRequestCategory()
  • setMoneyRequestTag()
  • setMoneyRequestBillable()
  • setMoneyRequestParticipants()
  • updateMoneyRequestDate()
  • updateMoneyRequestBillable()
  • updateMoneyRequestReimbursable()
  • updateMoneyRequestMerchant()
  • updateMoneyRequestAttendees()
  • updateMoneyRequestTag()
  • updateMoneyRequestTaxAmount()
  • updateMoneyRequestTaxRate()
  • updateMoneyRequestDistance()
  • updateMoneyRequestCategory()
  • updateMoneyRequestAmountAndCurrency()
  • deleteMoneyRequest()

• /IOU/splitBill.ts (18 functions)
  Split bill operations including creation, participant management, and share allocation.

  Functions

  • splitBill()
  • splitBillAndOpenReport()
  • startSplitBill()
  • completeSplitBill()
  • initSplitExpense()
  • initSplitExpenseItemData()
  • initDraftSplitExpenseDataForEdit()
  • addSplitExpenseField()
  • removeSplitExpenseField()
  • updateSplitExpenseField()
  • updateSplitExpenseAmountField()
  • saveSplitTransactions()
  • setSplitShares()
  • resetSplitShares()
  • setIndividualShare()
  • adjustRemainingSplitShares()
  • setDraftSplitTransaction()
  • clearSplitTransactionDraftErrors()

• /IOU/payment.ts (8 functions, ~500 lines)
  Payment processing, cancellation, and payment method management.

  Functions

  • sendMoneyElsewhere()
  • sendMoneyWithWallet()
  • canIOUBePaid()
  • canCancelPayment()
  • cancelPayment()
  • completePaymentOnboarding()
  • payMoneyRequest()
  • savePreferredPaymentMethod()

• /IOU/distanceRequest.ts (14 functions, ~700 lines)
  Distance and per diem expense operations including waypoint management, custom unit rates, and subrate handling.

  Functions

  • startDistanceRequest()
  • setCustomUnitRateID()
  • resetDraftTransactionsCustomUnit()
  • setCustomUnitID()
  • removeSubrate()
  • updateSubrate()
  • clearSubrates()
  • addSubrate()
  • setMoneyRequestDistance()
  • setMoneyRequestDistanceRate()
  • computePerDiemExpenseAmount()
  • getPerDiemExpenseInformation()
  • submitPerDiemExpense()
  • createDistanceRequest()

• /IOU/duplicate.ts (2 functions, ~600 lines)
  Duplicate transaction management including merge and resolve operations.
  We can move it to utils if needed

  Functions

  • mergeDuplicates()
  • resolveDuplicates()

• /IOU/trackExpense.ts (9 functions)
  Track expense operations including creation, deletion, conversion, and categorization.

  Functions

  • trackExpense()
  • getTrackExpenseInformation()
  • buildOnyxDataForTrackExpense()
  • deleteTrackExpense()
  • convertTrackedExpenseToRequest()
  • convertBulkTrackedExpensesToIOU()
  • categorizeTrackedExpense()
  • shareTrackedExpense()
  • addTrackedExpenseToPolicy()
  • getNavigationUrlAfterTrackExpenseDelete()

• /IOU/workflow.ts (11 functions)
  Expense report workflow operations including approval, submission, and lifecycle management.

  Functions

  • approveMoneyRequest()
  • unapproveExpenseReport()
  • submitReport()
  • reopenReport()
  • retractReport()
  • canApproveIOU()
  • canUnapproveIOU()
  • canSubmitReport()
  • assignReportToMe()
  • addReportApprover()
  • hasOutstandingChildRequest()

• /IOU/invoice.ts (3 functions)
  Invoice operations including sending and payment processing.

  Functions

  • sendInvoice()
  • payInvoice()
  • getSendInvoiceInformation()

• /IOU/utils.ts
  Utility functions and shared helpers used across IOU operations including validation, formatting, and common operations.

  Example functions: dismissModalAndOpenReportInInboxTab(), canApproveIOU(), etc.

• /IOU/index.ts
  A barrel file that re-exports functions from domain modules (payment, distanceRequest, splitBill, etc.) to keep backward compatibility and provide a single entry point for IOU operations.

---

Note: Since multiple modules use the same Onyx connection data, creating separate connection objects in each file wouldn’t be memory efficient.
Instead, we can centralize all Onyx connections in a shared file (for example, IOUConnectionManager.ts) and import them where needed.
We could also make this helper stricter and expose only specific getters, like:

• /actions/IOU/IOUConnectionManager.ts

import { Onyx } from "react-native-onyx";

let allTransactions: NonNullable<OnyxCollection<OnyxTypes.Transaction>> = {};

Onyx.connect({
  // ...
});

export function getAllTransactions() {
  return allTransactions;
}

export function getTransactionById(id: string) {
  return allTransactions[id];
}

What alternative solutions did you explore? (Optional)

• N/A
  Reminder: Please use plain English, be brief and avoid jargon. Feel free to use images, charts or pseudo-code if necessary. Do not post large multi-line diffs or write walls of text. Do not create PRs unless you have been hired for this job.

[parasharrajat]

This will be held for some days while we are migrating Onyx subscription.

[parasharrajat]

We are not looking for proposals currently.

[melvin-bot]

@parasharrajat, @greg-schroeder, @roryabraham Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!