Merge.js

function merge(data) {
    var length = data.length;
    
    if (length === 1) {
        return [data[0]];
    }
    
    if (length === 2) {
        if (data[0] > data[1]) {
            return [data[1], data[0]];
        }
                    
        return [data[0], data[1]];
    }
        
    var first = merge(data.slice(0, Math.ceil(length / 2)));
    var second = merge(data.slice(first.length));
    
    var result = [];
    
    while (first.length && second.length) {
        if (first[0] > second[0]) {
            result.push(second.shift());
        } else {
            result.push(first.shift());
        }
    }
    
    return result.concat(first, second);
}
    
merge([10, 5, 4, 6, 8, 2, 1, 0, 3, 9, 7]);