merging 3 arrays, max of 9

var index = 0;
    results = [],
    prevLen;

while(true) {
  r.albums[index] && results.push(r.albums[index]);
  r.tracks[index] && results.push(r.tracks[index]);
  r.artists[index] && results.push(r.artists[index]);

  if(prevLen == results.length || results.length >= 9) {
    break;
  }
  prevLen = results.length;
  index++;
}
results = results.splice(0,9)

C++0x version, not completely sure about correctness, but just to show use of initializer lists, auto typing and move semantics, renamed vars for better comparison with js version, and really, save for a few parentheses and types it's the same. I'm likely the only one of us who cares about this ;)

using std::vector;
vector<int>&& merge3() {
    vector<int> const src_a[3] = { { 1,2 }, { 3,4,5 }, { 6,7,8,9 } };
    vector<int> out;
    int rmax = std::min(9, src_a[0].size() + src_a[1].size() + src_a[2].size());

    for(int rx = 0; out.size() < rmax; ++rx) {
        auto src = src_a[rx % 3];
        int ex = rx / 3;
        if(src.size() > ex) out.push_back(src[ex]);
    }
    return results;
}