var arr = [0,0,1,0,0,0,1,1,0] // should return index 3
var arr = [0,0,1,0,0,0,1,1,0,0,0,0] // should return index 8
var arr = [0,0,1,0] // should return index 0

var arr = [0,0,1,0,0,0,1,1,0];
function amounts(c, i, arr) {
    var zeros = 0, onesTogether = 0, where = [], changes = 0, longest0s;

    if (c === 0 && arr[i+1] === 0 || c === 0 && arr[i-1] === 0) {
        zeros++;
    } else {
        longest0s = zeros;
        zeros = 0;
        changes++;
        where.push[i];
    }

    console.log('longest0s: ' + longest0s + '. changes: ' + changes + '. where: ' + where);
    return where;

}
arr.reduce(amounts);

[0,0,1,0,0,0,1,1,0]