@wealthx/borrow-capacity-lib/README.md

Borrow capacity calculation library for WealthX

# @wealthx/borrow-capacity-lib

A centralized TypeScript library for finance data computations used across WealthX applications.

## Overview

This package provides a comprehensive set of financial calculations including:

- **User Metrics**: LVR, equity, excess monthly surplus calculations
- **Borrow Capacity**: Loan capacity and repayment calculations
- **HEM Calculations**: Household Expenditure Measure calculations for Australia
- **History Data Processing**: Scenario finance history aggregation

## Installation

```bash
yarn add @wealthx/borrow-capacity-lib
```

## Types

The library exports comprehensive TypeScript types for all calculations:

```typescript
import {
  AccountCategory,
  AccountType,
  UserFinanceData,
  MonthlyFinanceData,
  BorrowCapacityParams,
  HEMCalculationParams,
  PeriodType,
  // ... and many more
} from "@wealthx/borrow-capacity-lib";
```

## Testing

Run the test suite:

```bash
yarn test
```

Run tests with coverage:

```bash
yarn test:coverage
```

## Development

### Setup

```bash
# Use the correct Node.js version
nvm use

# Install dependencies
yarn install
```

### Building

```bash
yarn build
```

### Linting

```bash
yarn lint
yarn lint:fix
```

## Formula References

- **Borrow Capacity**: Based on [WealthX Finance Documentation](https://wealthx.atlassian.net/wiki/spaces/WD/pages/86343838/Finance+Borrow+capacity+formula)

## License

UNLICENSED - Private package for WealthX internal use only.

## Contributing

This is a private package. Please follow the established patterns and ensure all calculations have corresponding test cases.