Retrieving the date from the final item in a JSON object using AngularJS

Question

Retrieving the date from the final item in a JSON object using AngularJS

In my web application built with AngularJS, I am dynamically creating objects. The goal is to allow users to load new events by clicking a button. To achieve this functionality, I need to determine the date of the last event loaded so that I can fetch the next ones.

Below is the code snippet responsible for generating the JSON object:

    services.getEvents().then(function(data){
        $scope.events = data.data;
    });

Here's a glimpse at the corresponding HTML:

    <li ng-repeat="event in events | orderBy:'-event_date' ">
      <span>{{event.event_date}},{{event.event_name}}, {{event.event_venue}}, {{event.event_description}} </span>
    </li>

Take a look at an example event from the list:

{
 "event_id":"1",
 "event_name":"Event 1",
 "event_date":"2014-09-26 00:00:00",
 "event_venue":"Limerick",
 "event_description":"stuff"
}

My question is - how can I extract the latest date from these events in order to send it back to the API? Am I approaching this problem incorrectly?

Furthermore, I see this as an opportunity to enhance my understanding of AngularJS.

javascript json angularjs

Answer 1

Answer №1

var myApp = angular.module("myApp", []);


function MainController ($filter) {
this.data = [
  
  {
 "event_id":"1",
 "event_name":"Event 1",
 "event_date":"2014-05-26 00:00:00",
 "event_venue":"Limerick",
 "event_description":"stuff"
}, {
 "event_id":"2",
 "event_name":"Event 1",
 "event_date":"2015-09-26 00:00:00",
 "event_venue":"Limerick",
 "event_description":"stuff"
}, {
 "event_id":"3",
 "event_name":"Event 1",
 "event_date":"2014-9-27 00:00:00",
 "event_venue":"Limerick",
 "event_description":"stuff"
}
  
];
 this.latestEvent =$filter('orderBy')(this.data,'-event_date')[this.data.length-1].event_date ;
 }

angular.module("myApp").controller("MainController", MainController);

<html ng-app="myApp">
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<body ng-controller="MainController as vm">
  <div class="container">
     <h3>Latest Event Date: {{vm.latestEvent}}</h3>
    
  </div>
 
</body>
  </html>

Answer 2

var myApp = angular.module("myApp", []);


function MainController ($filter) {
this.data = [
  
  {
 "event_id":"1",
 "event_name":"Event 1",
 "event_date":"2014-05-26 00:00:00",
 "event_venue":"Limerick",
 "event_description":"stuff"
}, {
 "event_id":"2",
 "event_name":"Event 1",
 "event_date":"2015-09-26 00:00:00",
 "event_venue":"Limerick",
 "event_description":"stuff"
}, {
 "event_id":"3",
 "event_name":"Event 1",
 "event_date":"2014-9-27 00:00:00",
 "event_venue":"Limerick",
 "event_description":"stuff"
}
  
];
 this.latestEvent =$filter('orderBy')(this.data,'-event_date')[this.data.length-1].event_date ;
 }

angular.module("myApp").controller("MainController", MainController);

<html ng-app="myApp">
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<body ng-controller="MainController as vm">
  <div class="container">
     <h3>Latest Event Date: {{vm.latestEvent}}</h3>
    
  </div>
 
</body>
  </html>

Answer 3

Answer №2

To retrieve the final element of an array, simply subtract 1 from the length property

elements[elements.length - 1].element_value

If the data received from the server is not organized in any specific order, it is recommended to filter the data before proceeding

var sortedElements = $filter('orderBy')($scope.elements, '-element_date');
var lastElementDate = sortedElements[sortedElements.length - 1].element_date

I trust this information will guide you in the right direction.

Answer 4

To retrieve the final element of an array, simply subtract 1 from the length property

elements[elements.length - 1].element_value

If the data received from the server is not organized in any specific order, it is recommended to filter the data before proceeding

var sortedElements = $filter('orderBy')($scope.elements, '-element_date');
var lastElementDate = sortedElements[sortedElements.length - 1].element_date

I trust this information will guide you in the right direction.

Answer 5

Answer №3

To retrieve the latest date from an array sorted in descending order on the server side, you can simply access the date of the first item like this:

events[0].event_date;

If sorting on the server side is not possible, you can achieve the same result on the client side by using the following code snippet:

events.sort(function(a, b){return new Date(a.event_date) < new Date(b.event_date);});

Then, to obtain the latest date value:

events[0].event_date;

Answer 6

To retrieve the latest date from an array sorted in descending order on the server side, you can simply access the date of the first item like this:

events[0].event_date;

If sorting on the server side is not possible, you can achieve the same result on the client side by using the following code snippet:

events.sort(function(a, b){return new Date(a.event_date) < new Date(b.event_date);});

Then, to obtain the latest date value:

events[0].event_date;

Retrieving the date from the final item in a JSON object using AngularJS

Answer №1

Answer №2

Answer №3

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