code: function min(comparer) {
  	    var min = (typeof comparer === 'function')
  	        ? function (x, y) { return comparer(x, y) < 0 ? x : y; }
  	        : function (x, y) { return x < y ? x : y; };
  	    return this.lift(new reduce_1.ReduceOperator(min));
  	}
docs: The Min operator operates on an Observable that emits numbers (or items that can be evaluated as numbers),
  and when source Observable completes it emits a single item: the item with the smallest number.
  
  <img src="./img/min.png" width="100%">
  
  @param {Function} optional comparer function that it will use instead of its default to compare the value of two items.
  @return {Observable<R>} an Observable that emits item with the smallest number.
  @method min
  @owner Observable