Zrób wiele tablicy w jednej tablicy

function flatten(arr) {
   // your code here    
}

var arrays = [
    ["1", "2", "3"],
    [true],
    [4, 5, 6]
];

console.log(flatten(arrays)); // ["1", "2", "3", true, 4, 5, 6];
Lively Lobster