Разгледах цялата задача, но така и не намерих причина да ми гърми някъде. Дори заместих някои части с даденото решение но нищо не промени и ги върнах. Някакви идеи? - https://pastebin.com/na4DN2Xw

**EDIT
Имах грешка в Steal, както и не бях сложил break нa for цикъла, но така и не успях да го направя за 100. Дава 80 с for и 100 с while.

https://pastebin.com/PyuHp0Vd

;-)

function treasureHunt(arr) {
    let initialLoot = arr.shift().split("|");
    let arrayL = initialLoot.length;

    // CAREFULL do not iterate an array that is being modified with shift() 
    // or unshift() !!!
    // for (let i = 0; i < arrayL; i++) {
    for (const line of arr) {
        // let currentCommandArray = arr.shift().split(" ");
        // let command = currentCommandArray.shift();
        let [command, ...currentCommandArray] = line.split(" ");

        switch (command) {
            case "Loot":
                for (let el of currentCommandArray) {
                    if (!initialLoot.includes(el)) {
                        initialLoot.unshift(el);
                    }
                }

                break;
            case "Drop":
                let startingIndex = Number(currentCommandArray[0]);

                if (startingIndex >= 0 && startingIndex < initialLoot.length) {
                    let oldLoot = initialLoot.splice(startingIndex, 1)
                    initialLoot.push(...oldLoot);
                    // initialLoot.push(initialLoot.splice(startingIndex, 1).join(""));
                }

                break;
            case "Steal":
                // let itemCount = Number(currentCommandArray[0]);
                // let index = initialLoot.length - itemCount;
                // let itemsToPrint = initialLoot.splice(index, itemCount);
                // console.log(itemsToPrint.join(", "));

                let index = Number(currentCommandArray);
                let stolenTreasure = initialLoot.slice(-index);
                initialLoot.splice(-index);
                console.log(stolenTreasure.join(', '));

                break;
        }
    }

    let itemSum = initialLoot.reduce((sum, initialTresure) => {
        return sum + initialTresure.length;
    }, 0) / initialLoot.length;

    // for (let el of initialLoot) {
    //     let itemLength = el.length;
    //     itemSum += itemLength;
    // }

    // initialLoot.length > 0 !!!
    // if (initialLoot.length >= 0) {
    if (initialLoot.length > 0) {
        // let averageGain = itemSum / initialLoot.length;
        // console.log(`Average treasure gain: ${averageGain.toFixed(2)} pirate credits.`);
        console.log(`Average treasure gain: ${itemSum.toFixed(2)} pirate credits.`);
    } else {
        console.log(`Failed treasure hunt.`);
    }
}