const dangerArray = [
    ["🎅", "👺"],
    [
        ["🎅", "🦁"],
        ["👹", "🎅"]
    ],
    [
        [
            ["🎅", "🐻"],
            ["👽", "🎅"]
        ],
        [
            ["🐯", "🎅"],
            ["🎅", "😈"]
        ]
    ]
];

function saveSanta(arr, returnSanta) {
    const consolidated = arr.reduce((acc, child) => {
        if (Array.isArray(child)) {
            acc.push(...saveSanta(child, returnSanta));
        } else {
            acc.push(child);
        }
        return acc;
    }, []);

    const santa = consolidated.filter(santa => santa === "🎅");
    const nefariousCreatures = consolidated.filter(santa => santa !== "🎅");

    return returnSanta ? santa : nefariousCreatures;
}

function displayResults() {
    const returnSanta = document.getElementById('returnSanta').checked;
    const results = saveSanta(dangerArray, returnSanta);
    document.getElementById('results').innerHTML = results.join(' ');
}  

document.getElementById('submitButton').addEventListener('click', displayResults);
  
console.log(`returnSanta: ${saveSanta(dangerArray, true)}`);
console.log(`nefariousCreatures: ${saveSanta(dangerArray, false)}`);