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Adding a running sum to a javascript object

I have a javascript object as below
var mydata=[
{"Club":"Blackburn","EventNo":1,"Pnts":3,"CumPnts":0},
{"Club":"Blackburn","EventNo":2,"Pnts":1,"CumPnts":0},
{"Club":"Blackburn","EventNo":3,"Pnts":4,"CumPnts":0},
{"Club":"Preston","EventNo":1,"Pnts":2,"CumPnts":0},
{"Club":"Preston","EventNo":2,"Pnts":4,"CumPnts":0},
{"Club":"Preston","EventNo":3,"Pnts":2,"CumPnts":0},]
I want to update the object so that CumPnts contains a running points total for each Club as below
{"Club":"Blackburn","EventNo":1,"Pnts":3,"CumPnts":3},
{"Club":"Blackburn","EventNo":2,"Pnts":1,"CumPnts":4},
{"Club":"Blackburn","EventNo":3,"Pnts":4,"CumPnts":8},
{"Club":"Preston","EventNo":1,"Pnts":2,"CumPnts":2},
{"Club":"Preston","EventNo":2,"Pnts":4,"CumPnts":6},
{"Club":"Preston","EventNo":3,"Pnts":1,"CumPnts":7},]
Any help would be much appreciated

Here is a function that loops through the list and updates it after it's been added. But I suspect that the events come in one at a time so there could be another function that can look the cumPtns obj and take from that. Here is for the current list.
var cumData = {};
var mydata=[
{"Club":"Blackburn","EventNo":1,"Pnts":3,"CumPnts":0},
{"Club":"Blackburn","EventNo":2,"Pnts":1,"CumPnts":0},
{"Club":"Blackburn","EventNo":3,"Pnts":4,"CumPnts":0},
{"Club":"Preston","EventNo":1,"Pnts":2,"CumPnts":0},
{"Club":"Preston","EventNo":2,"Pnts":4,"CumPnts":0},
{"Club":"Preston","EventNo":3,"Pnts":2,"CumPnts":0}];
function updateMyData() {
for (var i = 0; i < mydata.length; i++) {
var item = mydata[i];
if(cumData[item.Club] == undefined) {
cumData[item.Club] = {};
cumData[item.Club] = item.Pnts;
} else {
cumData[item.Club] = cumData[item.Club] + item.Pnts;
}
mydata[i].CumPnts = cumData[item.Club];
};
console.log(mydata);
//if you want to return it you can have this line below. Otherwise the object is updated so you'll probably want to do something with it once it's updated. Call back maybe?
return mydata;
}
updateMyData();

The first time it encounters a team it adds it to an array and so does with the corresponding cumPnts, so we can keep track of whether we checked a team earlier or not.
var tmArr = [];
var cumArr = [];
for(var i = 0; i < mydata.length; i++) {
var elm = mydata[i];
var club = elm.Club;
var points = elm.Pnts;
var idx = tmArr.indexOf(club);
if(idx > -1) {
cumArr[idx] += points;
elm.CumPnts = cumArr[idx];
}
else {
elm.CumPnts = points;
tmArr[tmArr.length] = club;
cumArr[cumArr.length] = points;
}
}
jsfiddle DEMO

'Uncaught TypeError: undefined is not a function' keeps showing up for different lines of code

I am trying to take a set of text, and when I hit a button have it change to a different set of text. I have been trying a lot of different methods, and cannot seem to get it to work. Here is a working Jsfiddle.
I keep getting 'Uncaught TypeError: undefined is not a function' for the line
var $rep = $update.textContent.substring(1);
I have changed this line of code, but will the get the same error on a different line of code within the same function.
function createAnswers() {
var i;
for (i = 0; i < 4; i++) {
var $update = $(".answers p")[i];
var $rep = $update.textContent.substring(1);
console.log($rep);
var answerText = document.createTextNode(randomImage.randomAnswers[i]);
if (usedImages.length >= 1) {
$rep.replaceWith(answerText);
}
$update.appendChild(answerText);
}
}
I am still pretty new at Javascript, so I may be missing something very obvious. Any constructive criticism will be helpful.

Your function should look like:
function createAnswers() {
var i,
$answers = $(".answers p");
for (i = 0; i < 4; i++) {
var $update = $answers[i];
var $rep = $update.textContent.substring(1);
var answerText = document.createTextNode(randomImage.randomAnswers[i]);
if (usedImages.length >= 1) {
$update.textContent = $update.textContent.replace($rep, answerText.textContent);
}
$update.appendChild(answerText);
}
}
You do not need to use jQuery functions after var $update = $(".answers p")[i];, because $update becomes an DOM node.

I figured it out. Thanks everybody for the help. I realized I needed to specify the use of text nodes, and updating the text node directly. Here is my final code:
function createAnswers() {
var i,
$update;
for (i = 0; i < 4; i++) {
$update = $(".answers p")[i];
console.log($update);
var answerText = document.createTextNode(randomImage.randomAnswers[i]);
if (usedImages.length === 0) {
$update.appendChild(answerText);
}
else {
$update.childNodes[1].nodeValue = randomImage.randomAnswers[i];
}
}
}

Why does the second loop execute before the first loop?

so this might be a repost, but I don't really know how to explain my second problem.
I have this code:
var paragraphsArray = new Array();
function setParagraphs(offSet)
{
offSet = offSet * 12;
for (var i = 1; i < 13; i++)
{
var parX = i + offSet;
var testASd = $.get('php/entryParagraphs.php', {idd: parX}).done(function(paragraph)
{
//clear paragraph1 div
document.getElementById("paragraph1").innerHTML = "";
//create p elements
var pElem = document.createElement("p");
pElem.setAttribute("id", "pEntry"+i);
document.getElementById("paragraph1").appendChild(pElem);
$("pEntry"+i).text(paragraph);
});
}
}
edited: I removed the second loop because it was unnecessary, for some reason the p element creation starts on i==13, which is the extra one that shouldn't even do.
for some reason the second loop executes first, so the paragraphArray is printed out as undefined. I managed to "fix" the order with the setTimeout() function, BUT I still get the undefined message, instead of the value. In the first loop the value is printed out fine, but if I try and put it in a $("p").text(paragraph); I also get undefined. So although I was right about the execution order, the problem is still there!

Because first is in ajax call, declare paragraphsArray in global space and use a callback function, try this:
*Updated
var paragraphsArray = [];
function setParagraphs(offSet) {
offSet = offSet * 12;
var request = 0;
for (var i = 1; i < 13; i++) {
var parX = i + offSet;
var testASd = $.get('php/entryParagraphs.php', {idd: parX}).done(function(paragraph) {
request++;
paragraphsArray[request] = paragraph;
console.log(paragraphsArray[request]);
if (request === 12) {
alert('first');
callback();
}
});
}
}
function callback() {
for (var i = 1; i < 13; i++) {
console.log(paragraphsArray[i]);
}
alert('second');
}

Run the second loop inside of the first loop.
function setParagraphs (offSet) {
//paragraphs
var testing = 0;
var paragraphsArray = new Array();
offSet = offSet * 12;
for (var i=1;i<13;i++) {
var parX = i + offSet;
var testASd = $.get('php/entryParagraphs.php', { idd: parX }).done(function(paragraph) {
paragraphsArray[i] = paragraph;
console.log(paragraphsArray[i]);
alert('first');
for (var i=1;i<13;i++) {
console.log(paragraphsArray[i]);
alert('second');
}
});
}
}

$.get is async function. 1st cycle will just send requests and wouldn't wait for response, so 2nd cycle will start right after first, without getting response of $.get function. Thats why console.log(paragraphsArray[i]); in 2nd cycle shows undefined.
You only can handle response in first cylce.
You can use $("p").text(paragraph); only like in this example:
var testASd = $.get('php/entryParagraphs.php', { idd: parX }).done(function(paragraph) {
paragraphsArray[i] = paragraph;
console.log(paragraphsArray[i]);
alert('first');
$("p").text(paragraph);
});
You can't use variables, which are assigned in function
function(paragraph) {
paragraphsArray[i] = paragraph;
console.log(paragraphsArray[i]);
alert('first');
$("p").text(paragraph);
}
outside of this function.
To achieve what you want you have to use another approach.
HTML will be:
<div id='paragraphs'>
</div>
JS code:
var testASd = $.get('php/entryParagraphs.php', { idd: parX }).done(function(paragraph) {
$("#results").append("<p>"+paragraph+"</p>")
});
You should use ~ this code. I just show you approach.

Scroll text method, works with arrays, not with string

Basic javascript function to scroll the text in the title bar, I'm calling it via a setInterval("rotateTitle()", 1000); call after onload.
This function, which takes text from an array, works perfectly.
var counter = 0;
function rotateTitle() {
var baseTitle = "www.mydomain.com - now with JavaScript";
var titleArray = new Array("a","b","c","d","e","f","g");
var titleString = "abcdefg";
var scrollText = getNextScroll(titleArray);
window.document.title=baseTitle.concat(scrollText);
}
function getNextScroll(inValue) {
var str = " ";
for (var i = 0; i<inValue.length; i++) {
var index = i+counter;
if (i+counter >= inValue.length) {
index -= inValue.length;
}
str += inValue[index];
}
counter++;
if (counter > inValue.length) {
counter = 0;
}
return str;
}
Edited here for clarity:
Now if I rewrite the function to scroll a string (not an array), I change the line
str += inValue[index];
to
str.concat(inValue.charAt(index));
and change getNextScroll(titleArray) to getNextScroll(titleString), the script seems to execute, but only the baseTitle is shown.
Why is this wrong?

You have to assign the result of str.concat back to str; otherwise you'll miss the concat operation. Instead of charAt you must use inValue[index].
Do like this:
str = str.concat(inValue[index]);
Here's a JS Bin: http://jsbin.com/aCEBAju/2/
In your original code you have this:
str.concat(inValue.charAt(index));
debugging in Chrome it barks: array has no method charAt.

The solution to the problem is that str.concat(inValue.charAt(index)); must change to str = str.concat(inValue.charAt(index)); or str += inValue.charAt(index);. Str must be assigned the new value. This is the entire working function:
var counter = 0;
function rotateTitle() {
var baseTitle = "www.berrmal.com - now with JavaScript";
var titleArray = new Array("b","e","r","r","m","a","l"); //no longer necessary
var titleString = "berrmal: bigger, longer, uncut";
var scrollText = getNextScroll(titleString);
window.document.title=baseTitle.concat(scrollText);
}
function getNextScroll(inString) {
var str = " ";
for (var i = 0; i<inString.length; i++) {
var index = i+counter;
if (i+counter >= inString.length) {
index -= inString.length;
}
str += inString.charAt(index);
}
counter++;
if (counter > inString.length) {
counter = 0;
}
return str;
}
I figured out the answer to the problem based on Leniel Macaferi's answer, though his posted code is not correct. This method runs successfully in Firefox 23.0 with no error in the console.

Merging arrays in JavaScript not working

When I try var a = ar_url2.concat(ar_desc2); to join my arrays into one it returns null. I'm sure it's trivial but I spent a few hours stuck on this now and an explanation as why this is happening would be great. In my code bellow I tried while(ar_url2.length)a.push(ar_url2.shift()); and it returns same null...
function agregar() {
var i = 0,
textarea;
var ar_desc = [];
while (textarea = document.getElementsByTagName('textarea')[i++]) {
if (textarea.id.match(/^desc_([0-9]+)$/)) {
ar_desc.push(textarea.id);
}
}
var desc_count_demo = document.getElementById('desc_count').value;
var desc_count = desc_count_demo - 1;
i = 0;
var ar_desc2 = [];
var campo = null;
while (i <= desc_count) {
campo = document.getElementById(ar_desc[i]).value;
ar_desc2[ar_desc[i]] = campo;
i++;
}
i = 0;
var input;
var ar_url = [];
while (input = document.getElementsByTagName('input')[i++]) {
if (input.id.match(/^url_([0-9]+)$/)) {
ar_url.push(input.id);
}
}
var url_count_demo2 = document.getElementById('url_count').value;
var url_count2 = url_count_demo2 - 1;
i = 0;
var ar_url2 = [];
while (i <= url_count2) {
campo = document.getElementById(ar_url[i]).value;
ar_url2[ar_url[i]] = campo;
i++;
}
// var a = Array.prototype.concat.call(ar_url2, ar_desc2);
while (ar_url2.length) a.push(ar_url2.shift());
function url(data) {
var ret = [];
for (var d in data)
ret.push(encodeURIComponent(d) + "=" + encodeURIComponent(data[d]));
return ret.join("&");
}
window.open('alta1.php?'+url(a));
}
EDIT: If I pass to function url(ar_url2) or url(ar_desc2) the returned values in the URL are
http://localhost/proj1/alta1.php?url_0=inpit&url_1=input
and
http://localhost/proj1/alta1.php?desc_0=input&desc_1=input
But still cannot merge both into one...

One thing I see is your ar_url Array is filled by:
while(input=document.getElementsByTagName('input')[i++]){
if(input.id.match(/^url_([0-9]+)$/)){
ar_url.push(input.id);
}
}
Since you the putting the whole id in the array, it will be filled with things like: 'url_0', 'url_1', 'url_2', etc...
Later you do:
ar_url2[ar_url[i]] = campo;
When you index into ar_url, you get out the 'url_XXX' strings. That means you are setting the 'url_XXX' properties on ar_url2 instead of filling in the elements of the array.
Try changing your second loop to:
while(input=document.getElementsByTagName('input')[i++]){
var result;
if(result = input.id.match(/^url_([0-9]+)$/)){
ar_url.push(+result[1]);
}
}
To use the value captured in the ([0-9]+) portion of the RegExp instead of the entire 'url_XXX' string.