added accumulateProof fn

[Egge21M]

Added a utility function that will iterate over an array of proofs and gather them until a certain amount is reached. The function will take a strategy argument, which determines in which order proofs are selected:

• middle: Will alternate between lowest and highest amount
• ascending: Will start with the lowest amount and work its way up
• descending: Will start with the highest amount and work its way down.

The function returns an object with three properties:

• base: An array that contains all proofs but the last one (Proof[)]
• exceeds: The last Proof that was added to the result (which will make the total amount of gathered proofs greater than the required amount (Proof)
• excess: The amount that the total amount of gathered proofs exceeds the required amount. (number)

[BilligsterUser]

could you pls run

npm run lint

and

npm run format

[BilligsterUser]

Let's use the Array<> notation, for consistency. 😅

[BilligsterUser]

just to make the linter (and me) happy

case 'middle':
			while (total < requiredAmount) {
				const first = temp.shift();
				if (!first) { break }
				total += first.amount;
				result.push(first);
				if (total >= requiredAmount) {
					break;
				}
				const last = temp.pop();
				if (!last) { break }
				total += last.amount;
				result.push(last);
			}
			break;

		

[BilligsterUser]

why not

const temp = proofs.slice()
	if (strategy === 'descending') {
		temp.sort((a, b) => b.amount - a.amount);
	} else {
		temp.sort((a, b) => a.amount - b.amount);
	}

and than

case 'descending':
case 'ascending':
	for (let i = 0; i < temp.length; i++) {
		total += temp[i].amount;
		result.push(temp[i]);
		if (total >= requiredAmount) {
			break;
		}
	}
	break;

[Egge21M]

could you pls run

npm run lint

eslint yells at me for using !... The reason for non-null assertion in this case is that shift is typed to return a value or undefined if the array is empty. In my case I know that the array will not be empty, because the loop will only run if temp.length is truthy... Unfortunately the TS does not catch this and will complain about first possibly being undefined...

[gandlafbtc]

We can expose this function on index.ts. maybe at some point it will make sense to expose an util object or something, it's becoming more and more helper methods. Starts to get confusing

[gandlafbtc]

@BilligsterUser @Egge7 what shall we do with this PR? Has everything been resolved?

[BilligsterUser]

I´m still waiting for @Egge7