Unique Sorted Set with binary search

collection.js

class Collection {

   constructor (opts = {}) {
      this.list = [];
      this.length = 0;

      var isFn = $.is.function;

      if (opts.key) {
         var keyType = $.object.type(opts.key);
         if (keyType === 'function') {
            this.isHashed = true;
            this.map = {};
            this.key = opts.key;
         }
         else if (keyType === 'string') {
            this.isHashed = true;
            this.map = {};
            this.key = function (elem) {
               return $.object.result(elem, opts.key);
            };
         }
      }

      this.equals = isFn(opts.equals) ? opts.equals : function (a, b) {
         return a === b;
      };

      this.comparator = isFn(opts.comparator) ? opts.comparator : function (a, b) {
         if (b && b.localeCompare) return b.localeCompare(a);
         else return this.equals(a, b) ? 0 : a > b ? 1 : -1;
      };
   }

   get ( input ) {
      if (this.isHashed) {
         if (this.map[ input ]) return this.map[ input ];

         var key = this.key( input );
         if (key && this.map[ key ]) return this.map[ key ];

         key = this.list[ input ];
         if (key && this.map[ key ]) return this.map[ key ];
      } else {
         return this.input[ input ];
      }
   }

   indexOf ( element ) {
      var i, low = 0, high = this.length;

      while (low < high) {
         i = (low + high) / 2 | 0;
         var cursor = this.comparator(this.get( i ), element);
         if (cursor > 0) low = i + 1;
         else if (cursor < 0) high = i;
         else return i;
      }

      return high < 0 ? high : ~high;
   }

   insert ( element ) {
      var key = this.isHashed ? this.key( element ) : element;
      var index = this.indexOf( key );

      if (index < 0) {
         var array = this.list;
         array.splice(~index, 0, key);
         if (this.isHashed) this.map[key] = element;
         this.length = array.length;
      }

      return this;
   }

   remove ( key ) {
      var index = this.indexOf( this.isHashed ? this.get( key ) : key );
      console.log(index, key);
      if (index >= 0) {
         var removal = this.list.splice( ~index, 1 );
         this.length = this.list.length;
         if (this.isHashed) {
            this.map = $.object.omit(this.map, removal[0]);
         }
      }

      return this;
   }

}

function randid () {
   var id = ('' + Math.pow(10, $.utils.random(1, 10))).replace(/1|0/g, function () {
      return (0 | Math.random() * 16).toString(16);
   });
   return id;
}

export default {

   controller () {
      var set = new Collection({ key: 'id' });
      console.time('timeTaken');
      for (var i = 5; i >= 1; i--) {
         set.insert({ id: i, name: randid() });
      }
      set.remove(2);
      set.remove(3);
      console.timeEnd('timeTaken');
      console.log( set.length, set.list, set.get(2) );
   }

};