get data and value from jquery array

Question

I am trying to check if there is an id existing in an array, if the id is already there, then I will update that id's value. Otherwise I will push the id and its value into the array. How can I achieve that with jquery?

I have tried but it doesn't work, but double the size of the array

 $(itemData).each(function() {
 var name = $(this).data("name");
 var value = parseFloat($(this).data("amount"));
 if(dataArr.length == 0) {
 dataArr.push([name, value]);
 } else {
 $.each(dataArr, function(n, v) {
 if(name == n) {
 v += value;
 }else {
 dataArr.push([name, value]);
 }
 });
 }
 });

Answer 1

You are close, try the following:

$(function() {
 var itemData = $('.item-data'),
 dataArr = [];
 $(itemData).each(function() {
 var name = $(this).data("name");
 var value = parseFloat($(this).data("amount"));
 var found = false;
 $.each(dataArr, function(index, val) {
 if (!found && name == val[0]) {
 val[1] += value;
 found = true;
 }
 });
 if (!found) {
 dataArr.push([name, value]);
 }
 });
 console.log('dataArray = ', dataArr);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="item-data" data-name="name1" data-amount="1"></div>
<div class="item-data" data-name="name2" data-amount="2"></div>
<div class="item-data" data-name="name1" data-amount="3"></div>
<div class="item-data" data-name="name2" data-amount="4"></div>
<div class="item-data" data-name="name3" data-amount="5"></div>

Answer 2

I guess it would be easier with a hash (object literal), not an array:

var dataObj = {};
$(itemData).each(function() {
 var name = $(this).data("name");
 var value = parseFloat($(this).data("amount"));
 dataObj[name] = typeof dataObj[name] !== 'undefined' ? dataObj[name] + value : value;
});