Most efficient way to create a zero filled JavaScript array?

Question

What is the most efficient way to create an arbitrary length zero filled array in JavaScript?

Answer 1

This concat version is much faster in my tests on Chrome (2013-03-21). About 200ms for 10,000,000 elements vs 675 for straight init.

function filledArray(len, value) {
    if (len <= 0) return [];
    var result = [value];
    while (result.length < len/2) {
        result = result.concat(result);
    }
    return result.concat(result.slice(0, len-result.length));
}

Bonus: if you want to fill your array with Strings, this is a concise way to do it (not quite as fast as concat though):

function filledArrayString(len, value) {
    return new Array(len+1).join(value).split('');
}