anchor-loan-calculator.js

const MONTHLY_PAYMENT = 558;
const BORROW_APR = 0.2607;
const REWARD_APR = 0.446;
const TARGET_LTV = 0.3;
const ETH_STAKING_APR = 0.0483;

let collateral = 100000;
let debt = 30000;
let cost = 0;

for (let month = 1; debt > 0; month++) {
  const interest = (debt * BORROW_APR) / 12;
  const reward = (debt * REWARD_APR) / 12;

  debt += interest - reward;

  if (debt > MONTHLY_PAYMENT) {
    cost += MONTHLY_PAYMENT;
    debt -= MONTHLY_PAYMENT;
  } else {
    cost += debt;
    debt = 0;
  }

  cost += (collateral * ETH_STAKING_APR) / 12;
  collateral = debt / TARGET_LTV;

  console.log(
    `month ${month},`,
    `debt: $${debt.toFixed(2)},`,
    `cost: $${cost.toFixed(2)}`
  );
}