################################################################
#####################    OOJS Stamps          ##################
################################################################

var StampCollection = function(stamps){
  this.stamps = stamps
}

StampCollection.prototype.stampNamed = function (stampName) {
  return this.stamps.find(function(stamp){
    return stamp.name === stampName;
  })
}

StampCollection.prototype.stampsIssued = function (issueDate) {
  return this.stamps.filter(function(stamp){
    return stamp.issueDate === issueDate;
  })
}

StampCollection.prototype.value = function() {
  return sum = this.stamps.reduce(function(total,stamp){
    return total + stamp.maximumAppraisal()
  }, 0)
}
###########################################################################
 ####################    OOJS Stamp Collection          ##################
###########################################################################
var StampCollection = function(stamps){
  this.stamps = stamps
}

StampCollection.prototype.stampNamed = function (stampName) {
  return this.stamps.find(function(stamp){
    return stamp.name === stampName;
  })
}

StampCollection.prototype.stampsIssued = function (issueDate) {
  return this.stamps.filter(function(stamp){
    return stamp.issueDate === issueDate;
  })
}

StampCollection.prototype.value = function() {
  return sum = this.stamps.reduce(function(total,stamp){
    return total + stamp.maximumAppraisal()
  }, 0)
}

###########################################################################
 ####################    OOJS Stamp Collection          ##################
###########################################################################
var Stamp = function(params) {
  this.name = params.name;
  this.issueDate = params.issueDate;
  this.appraisalValues = params.appraisalValues;
}

Stamp.prototype.averageAppraisal = function() {
  var sum = this.appraisalValues.reduce(function(a,b){
    return a + b
  }, 0);
  return sum / this.appraisalValues.length;
}

Stamp.prototype.maximumAppraisal = function() {
  var max = 0;
  for(var i = 0; i < this.appraisalValues.length; i++){
    if( this.appraisalValues[i] > max){
      max = this.appraisalValues[i]
    }
  }
  return max;
}