SOURCE

function printprops(o) {
    for (let p in o) {
        console.log(`${p}:${o[p]} \n`)
    }
}
function distance(x1, y1, x2, y2) {
    let dx = x2 - x1;
    let dy = y2 - y1;
    return Math.sqrt(dx * dx + dy * dy);
}

function factorial(x) {
    if (x <= 1) return 1;
    return x * factorial(x - 1);
}

printprops({ a: 1, b: 2, c: { d: 3 } });

console.log('distance', distance(3,0,3,4));

console.log('factorial:',factorial(3));