in src/lib/sortedList.js [79:85]
SortedList.prototype.insertOne = function(val) {
var pos = this.bsearch(val);
if (this._unique && this.key(val, pos) != null) return false;
if (!this._filter(val, pos)) return false;
this.splice(pos+1, 0, val);
return pos+1;
};