#403 find-highest-commodity-price

You are given a list of commodity price records, where each record contains:

• commodity (string) → name of the commodity
• price (number) → price of the commodity
• timestamp (number) → UNIX timestamp when the price was recorded

Your task is to implement a function that finds the highest price of a given commodity up to a specified timestamp.

Example

const records = [
  { commodity: "gold", price: 100, timestamp: 1 },
  { commodity: "gold", price: 120, timestamp: 3 },
  { commodity: "silver", price: 50, timestamp: 2 },
  { commodity: "gold", price: 90, timestamp: 5 },
];

findHighestPrice(records, "gold", 3);
// Expected output: 120

findHighestPrice(records, "gold", 1);
// Expected output: 100

findHighestPrice(records, "silver", 3);
// Expected output: 50

findHighestPrice(records, "silver", 1);
// Expected output: null (no records available before timestamp 1)

Requirements

• If no record exists for the commodity before or at the given timestamp, return null.
• The function should handle multiple commodities.
• Timestamps are guaranteed to be positive integers.
• Records may not be sorted by timestamp.