Treasure Hunt

function treasureHunt(line) {

    let treasure = line
        .shift()
        .split('|');

    line.forEach(tr => {

        let current = tr.split(' ');
        let command = current.shift();

        if (command === 'Yohoho!') {
            return;
        }

        if (command === 'Loot') {

            for (let i = 0; i < current.length; i++) {

                if (!treasure.includes(current[i])) {

                    treasure.unshift(current[i]);
                }
            }
        }
        if (command === 'Drop') {
            let index = Number(current[0]);
            let moved = treasure[index];
            if (index >= 0) {
                treasure.splice(index, 1);
                treasure.push(moved);
            }

        }
        if (command === 'Steal') {
            let stolenItems = '';
            let index = Number(current[0]);

            if (index < treasure.length) {

                stolenItems = treasure.splice(treasure.length - index, index);
                console.log(stolenItems.join(', '));

            } else {

                stolenItems = treasure.splice(0).join(', ');
                console.log(stolenItems);
            }
        }
    });

    let numberOfLoots = treasure.length;
    let points = treasure
        .join('')
        .length;

    if (numberOfLoots > 0) {
        console.log(`Average treasure gain: ${(points / numberOfLoots).toFixed(2)} pirate credits.`);
    } else {
        console.log("Failed treasure hunt.");
    }
}

treasureHunt([
    'Diamonds|Silver|Shotgun|Gold',
    'Loot Silver Medals Coal',
    'Drop -1',
    'Drop 1',
    'Steal 12',
    'Yohoho!'
]);