Function normalizeSelection

static/editor.md/lib/codemirror/lib/codemirror.js:1969–1983

(ranges, primIndex)

  // build a selection out of it. 'Consumes' ranges array (modifying
  // it).
  function normalizeSelection(ranges, primIndex) {
    var prim = ranges[primIndex];
    ranges.sort(function(a, b) { return cmp(a.from(), b.from()); });
    primIndex = indexOf(ranges, prim);
    for (var i = 1; i < ranges.length; i++) {
      var cur = ranges[i], prev = ranges[i - 1];
      if (cmp(prev.to(), cur.from()) >= 0) {
        var from = minPos(prev.from(), cur.from()), to = maxPos(prev.to(), cur.to());
        var inv = prev.empty() ? cur.from() == cur.head : prev.from() == prev.head;
        if (i <= primIndex) --primIndex;
        ranges.splice(--i, 2, new Range(inv ? to : from, inv ? from : to));
      }
    }
    return new Selection(ranges, primIndex);
  }

  function simpleSelection(anchor, head) {
    return new Selection([new Range(anchor, head || anchor)], 0);