atrivedi1 / get_liquidatable_loan_algo

Liquidate the Loans!

Installation

1. Navigate to the target directory in the terminal and run the following command https://github.com/atrivedi1/get_liquidatable_loan_algo.git
2. In the getLiqidatableLoans folder, run:

• npm install
• npm run test

Implementation

As it pertains to my v1 implementation of the getLiquidatableLoans function, there are a few things worth calling out:

1. I assumed that the data provided was merely sample data, and that the implementation of getLiquidatableLoans would ultimately need to handle:

• Much larger data sets
• Defaulted Loans

2. I assumed that the data in the loans.json and eth-prices.json files would always be sorted in decesending order.

3. Given #1 and #2, I decided to leverage a binary search algorithm twice in my implementation: first, to identify the price of ETH at a given point in time; and second, to determine which loans, if any, are in default (based on the given time)

Test

To validate my implementation I added an additional loan object to the end of loans.json with a filledAt value ~90 days before the first timestamp in eth-prices.json and created the following tests:

1. Confirm that the getLiquidatableLoans function returns an array of length 7 with the given sample input: 1558650159442

2. Confirm that the getLiquidatableLoans function returns an array of length 8 when the given time input is equal to the FIRST timestamp in the eth-prices.json file - meaning that the result should include a defaulted loan

3. Confirm that the getLiquidatableLoans function returns an array of length 7 when the given time input is equal to the LAST timestamp in the that the getLiquidatableLoans function returns an array of length 7 file (to ensure that the binary search functionality works at the extremes of the provided dataset)

4. Confirm that that the getLiquidatableLoans function returns an empty array when the given time input is OUTSIDE of the date range in the eth-prices.json file.

Outstanding Items

If I had more time, I would refector my binary search implementation to address:

1. Readability - for v1, I abstracted out the binary search logic such that I can leverage it to both find defaulted loans AND the price of ETH at a given point in time. However in doing so, the code is a little harder to reason about.

2. Conciseness - Right now I have some verbose MVP logic to handle edge cases (see note on line 84 of getLiquidatableLoans/main.js).