Invoice Parser - Coding Challenge

Challenge Overview

This coding challenge asks you to build an intelligent invoice parser using the OpenAI API. Your task is to develop a TypeScript application that can extract structured data from raw invoice text using OpenAI's language models.

Requirements

Functional Requirements

1. Create a TypeScript application that parses invoice text using OpenAI.
2. Implement a solution that extracts structured data including:
   • Invoice number
   • Invoice date
   • Due date
   • Vendor information
   • Customer information
   • Line items (description, quantity, unit price, amount)
   • Invoice totals (subtotal, tax, total amount)
   • Currency
   • Payment terms
3. Handle various invoice formats gracefully.
4. Include proper error handling and validation.

Technical Requirements

1. Must use TypeScript with proper typing.
2. Must use OpenAI's API with structured outputs (JSON response format).
3. Write clean, maintainable code with appropriate documentation.
4. Include comprehensive unit tests using Jest.
5. Provide clear instructions for running your application.

Getting Started

Prerequisites

• Node.js (v14 or higher)
• npm or yarn
• OpenAI API key

Installation

# Clone the repository
git clone [repository-url]
cd invoice-parser-challenge

# Install dependencies
npm install

# Set up your OpenAI API key
# Copy the .env.template to .env and add your API key
cp .env.template .env

# Edit the .env file to add your actual API key
# OPENAI_API_KEY=your_api_key_here

Running the Application

# Build the TypeScript code
npm run build

# Run the application
npm start

# Run in development mode (with ts-node)
npm run dev

Running Tests

npm test

Example Code

An example implementation is provided in the src directory with a basic invoice parser class and corresponding unit tests. This is intended to give you a starting point, but you should extend and improve upon it to create a robust solution.

Evaluation Criteria

Your submission will be evaluated based on:

1. Correctness: Does the parser accurately extract invoice data?
2. Code Quality: Is the code well-structured, cleanly written, and properly documented?
3. TypeScript Usage: Is TypeScript properly utilized with appropriate typing?
4. Error Handling: How well does the application handle edge cases and errors?
5. Testing: Are there comprehensive tests that cover the functionality?
6. API Usage: Is the OpenAI API used efficiently and effectively?

Submission Guidelines

1. Create a private GitHub repository with your implementation.
2. Include a README with instructions for running your code and any additional notes.
3. Share access with [reviewer's GitHub username].

Time Expectation

This challenge is designed to be completed within a 45-minute interview session. Focus on a simple, functioning solution that demonstrates your understanding of TypeScript and the OpenAI API.