Transaction Log Processor

Problem Statement

You are given a transaction log file (transactions.json) containing details of financial transactions:

[
  { "id": 1, "type": "credit", "amount": 200, "account": "A123" },
  { "id": 2, "type": "debit", "amount": 100, "account": "A123" },
  { "id": 3, "type": "credit", "amount": 500, "account": "B456" },
  { "id": 4, "type": "debit", "amount": 300, "account": "A123" },
  { "id": 5, "type": "credit", "amount": 400, "account": "B456" }
]

Tasks

1. Parse the File

   • Read the file using Deno.readTextFileSync() and parse the JSON content.

2. Summarize Account Balances

   • Calculate the net balance for each account (credit - debit).
   • Output the balances in an object like this:

     {
       A123: 100,
       B456: 900
     }

3. Handle Errors Gracefully

   • If the file is missing or malformed, catch the error and display a user-friendly message like:
     "Error: Unable to process transactions. Please check the file and try again."

4. Bonus Challenge [optional]

   • If any transaction has a negative amount or an unknown type, log an error:
     "Transaction ID [id] has invalid data: [error description]"
   • Skip invalid transactions and proceed with the rest.

Transaction Log Processor - Expected Output (for the given data)

1. Account Balances

• ACC001:
  1500 (credit) + 800 (credit) - 500 (debit) - 300 (debit) - 50 (debit) - 700 (debit) = $750.00
• ACC002:
  2000 (credit) + 500 (credit) - 1200 (debit) - 100 (debit) = $1200.00

---

2. Category Summaries

Credits:

• ACC001:
  1500 (salary) + 800 (refund) = $2300.00
• ACC002:
  2000 (bonus) + 500 (freelance) = $2500.00

Debits:

• ACC001:
  500 (groceries) + 300 (utilities/electricity) + 50 (snacks) + 700 (shopping/clothes) = $1550.00
• ACC002:
  1200 (rent) + 100 (entertainment/movies) = $1300.00

---

3. Transaction Breakdown

• Total Transactions: 10
• Credit Transactions: 5
• Debit Transactions: 5

---

4. Tag-based Summaries

• Salary: $1500.00
• Groceries: $500.00
• Bonus: $2000.00
• Rent: $1200.00
• Entertainment/Movies: $100.00
• Shopping/Clothes: $700.00
• Snacks: $50.00
• Freelance: $500.00