Get Array Based on samecategoryname using anjularjs - angularjs

Question

I have a Array has given below. In this array some objects contain with Key catagoryName. For each seperate CategoryName i need to get the count where ReadDate is null.
QUESTIONS HIGHLIGHTED:
Push into Array based on each Category ( category names might be 'N' number ).
Get the each category count where ReadDate is null.
.controller('testController',function($scope,$rootScope){
$rootScope.messages = [
{
"IntMessageUserId": 9,
"ReadDate": null,
"MessageSubject": "HOLY CRAP ",
"MessageText": "blah blah blah",
"Priority": 1,
"PriorityDescription": "High",
"StartDate": "2017-01-19T00:00:00",
"EndDate": "2017-07-01T00:00:00",
"IntMessageCategoryId": 36,
"CategoryName": "a New Category By Dave",
"CategoryDescription": "Only a couple",
"ActiveSw": true
},
{
"IntMessageUserId": 110,
"ReadDate": "null",
"MessageSubject": "Test_chm2",
"MessageText": "Test_chm2",
"Priority": 2,
"PriorityDescription": "Urgent",
"StartDate": "2017-01-04T00:00:00",
"EndDate": "2017-06-02T00:00:00",
"IntMessageCategoryId": 39,
"CategoryName": "Alerts",
"CategoryDescription": "Alerts",
"ActiveSw": true
},
{
"IntMessageUserId": 117,
"ReadDate": "2017-05-05T06:35:00",
"MessageSubject": "Test_chm2",
"MessageText": "Test_chm2",
"Priority": 1,
"PriorityDescription": "High",
"StartDate": "2017-01-04T00:00:00",
"EndDate": "2017-06-02T00:00:00",
"IntMessageCategoryId": 39,
"CategoryName": "Alerts",
"CategoryDescription": "Alerts",
"ActiveSw": true
},
{
"IntMessageUserId": 113,
"ReadDate": "2017-05-03T08:48:00",
"MessageSubject": "Testing PSC",
"MessageText": "Psc note that displays until May 26",
"Priority": 1,
"PriorityDescription": "High",
"StartDate": "2017-04-24T09:31:00",
"EndDate": "2017-05-26T09:31:00",
"IntMessageCategoryId": 59,
"CategoryName": "Alerts PSC",
"CategoryDescription": "Alerts PSC",
"ActiveSw": true
},
{
"IntMessageUserId": 130,
"ReadDate": null,
"MessageSubject": "17/18 Parking Pass sale dates",
"MessageText": "Parking Passes will be available for purchase for the 17/18 school year for all current Juniors starting on June 1st. Sophomores may purchase passes starting on August 1st. Sales are in person only at the school district offices. You must fill out our parking permit form, Show your current drivers license, and proof of insurance. Passes will be sold for $50.00 for the school year. \r\n\r\n",
"Priority": 0,
"PriorityDescription": "Normal",
"StartDate": "2017-05-05T10:40:00",
"EndDate": "2017-06-01T10:39:00",
"IntMessageCategoryId": 67,
"CategoryName": "High School Students",
"CategoryDescription": "High School students",
"ActiveSw": true
},
{
"IntMessageUserId": 111,
"ReadDate": "2017-05-03T08:50:00",
"MessageSubject": "Summer Sports Camps",
"MessageText": "Our summer sports camps flyers will be sent home in the next week or 2. Please check them out and see if you would like to enroll your child in a sports camp program. We encourage them to try something new, or improve their skills in an existing sport. ",
"Priority": 0,
"PriorityDescription": "Normal",
"StartDate": "2017-03-21T00:00:00",
"EndDate": "2017-05-15T00:00:00",
"IntMessageCategoryId": 69,
"CategoryName": "Athletic Department Notifications ",
"CategoryDescription": "Athletic Department.",
"ActiveSw": false
},
{
"IntMessageUserId": 131,
"ReadDate": null,
"MessageSubject": "End of Year Lunch balances",
"MessageText": "As we come to the end of our school year, a reminder that unused lunch funds will roll over to next school year and be available next year in the lunch line. If you have a student who is graduating and has unused funds, please consider donating those funds to a student in need.. You can contact the Food Service department at 513-555-5555 and we will be happy to coordinate this. Refunds of unused lunch funds can be issued for any student who's balance is greater than $5.00 Please fill out a refund form at the school office and they will be processed by our accounting department. Refund checks will be mailed within 30 days of receiving your forms in the office. Have a great summer. ",
"Priority": 0,
"PriorityDescription": "Normal",
"StartDate": "2017-05-05T10:45:00",
"EndDate": "2017-06-09T10:45:00",
"IntMessageCategoryId": 80,
"CategoryName": "Nutrition Services",
"CategoryDescription": "Nutrition Services",
"ActiveSw": true
}
];
What i tried till.
angular.forEach($rootScope.messages,function(value, key){
$scope.checkUnreadMessages(value.CategoryName);
})
var mainArray = [];
$scope.call = function(){
angular.forEach(arr, function(value, key){
var subarr = [];
subarr[value] = [];
angular.forEach($rootScope.messages, function(v, k){
if(value == v.CategoryName){
subarr[value].push(v.ReadDate);
}
})
mainArray.push(subarr);
})
}

Answer 1

I generally don't like to use extra library for a simple job which can be easily done in pure javascript.
https://repl.it/Hk45/2
Here is a link to a javascript compiler where you can see a solution.
Notice that all the work is done by the very simple function :
function fillOrInitiate(category, element){
if(categories[category]){
categories[category].push(element);
} else {
categories[category] = [];
categories[category].push(element);
}
}
Then just iterate through your data.
EDIT : Take care of your data, sometimes ReadDate is null and sometimes it is "null". However I took care of that in my example in the function CountReadDateNull.
You should not be able to visualize the data directly by printing final tab, but it is here as you can see on the second console.log

Answer 2

Why you are not using Underscore.js
Need to Extract Array Based on Category Name.
_.where( $rootScope.messages, {CategoryName: "searching category name"});
Get the each category count where ReadDate is null.
_.where( $rootScope.messages, {ReadDate: null}).length;

Answer 3

1) Iterate through an array of messages and check the same category name and then pushing it into new array, before that you need to group it using category name as the key.
var groupCategory = {};
angular.forEach($rootScope.messages, function (oldVal, newVal) {
if (oldVal.CategoryName === newVal.CategoryName) {
if (angular.isDefined(groupCategory[newVal.CategoryName])) {
groupCategory[newVal.CategoryName].push(newVal);
} else {
groupCategory[newVal.CategoryName] = [newVal];
}
}
});
2) Then, you can count the category group by filter/checking if ReadDate is null
var cnt = 0;
angular.forEach(sameCategoryObj, function (val) {
if(val.ReadDate === null) {
cnt++;
}
});