Как упростить код на JavaScript?⁠⁠

http://vigrius.esy.es/pikabu/ лови

<?

$arCoffes = array(

"coffe1"=>"10",

"coffe2"=>"20",

"coffe3"=>"40",

"coffe4"=>"20",

"coffe5"=>"20",

"coffe6"=>"80",

"coffe7"=>"20",

"coffe8"=>"70",

);

?>

price 10P

<br>

<?foreach($arCoffes as $key=>$coffee):?>

<input class = "coffees" type = "hidden" value = <?=json_encode($arCoffes)?>>

<?=$key?> - <?=$coffee?>

<input data-coffee = <?=$key?> class = "counter" name = "<?=$coffee?>" value = 0>

<br>

<?endforeach?>

<div class = "all">

0

</div>

<div class = "price">

0

</div>

<script>

$(function(){

counter = new counter();

counter.init();

})

var counter = function()

{

var self = this;

self.values = {};

self.all = 0;

self.init = function()

{

self.coffes = JSON.parse($(".coffees").val());

$(".counter").each(function(){

var input = $(this);

var coffee = $(this).data("coffee");

var val = $(this).val();

self.values[coffee] = val;

recount();

})

$(".counter").off("input").on("input",function(){

var input = $(this);

var coffee = $(this).data("coffee");

var val = $(this).val();

var oldVal = self.values[coffee];

if(val == "")

{

self.values[coffee] = 0;

}

else

{

self.values[coffee] = val;

}

recount(oldVal,val,coffee);

})

}

function recount(oldValue,newValue,coffee)

{

var values = self.values;

if(oldValue)

{

var minus = oldValue*self.coffes[coffee];

self.all-=minus;

self.counter-=parseInt(oldValue);

var plus = newValue*self.coffes[coffee];

self.all+=plus;

self.counter+=parseInt(newValue);

}

else

{

var keys = Object.keys(self.values);

for(var i = 0 ;i<keys.length;i++)

{

var nowKey = keys[i];

var nowVal = self.values[nowKey];

var objem = self.coffes[nowKey];

var sum = nowVal*objem;

self.all+=sum;

}

self.counter = 0;

}

$(".all").html(self.all);

console.log(self.counter);

$(".price").html(self.counter*10);

}

}