Function SortedIndex

docs/tests/v2/es6/js/sanddance.js:125972–126067

* Maintains a list of values, sorted by key.

()

 * Maintains a list of values, sorted by key.
 */
function SortedIndex() {
  var index = (0, _arrays.array32)(0),
      value = [],
      size = 0;

  function insert(key, data, base) {
    if (!data.length) return [];
    var n0 = size,
        n1 = data.length,
        addv = Array(n1),
        addi = (0, _arrays.array32)(n1),
        oldv,
        oldi,
        i;

    for (i = 0; i < n1; ++i) {
      addv[i] = key(data[i]);
      addi[i] = i;
    }

    addv = sort(addv, addi);

    if (n0) {
      oldv = value;
      oldi = index;
      value = Array(n0 + n1);
      index = (0, _arrays.array32)(n0 + n1);
      merge(base, oldv, oldi, n0, addv, addi, n1, value, index);
    } else {
      if (base > 0) for (i = 0; i < n1; ++i) {
        addi[i] += base;
      }
      value = addv;
      index = addi;
    }

    size = n0 + n1;
    return {
      index: addi,
      value: addv
    };
  }

  function remove(num, map) {
    // map: index -> remove
    var n = size,
        idx,
        i,
        j; // seek forward to first removal

    for (i = 0; !map[index[i]] && i < n; ++i); // condense index and value arrays


    for (j = i; i < n; ++i) {
      if (!map[idx = index[i]]) {
        index[j] = idx;
        value[j] = value[i];
        ++j;