Navigating live data and managing the view state within AngularJS

Question

Navigating live data and managing the view state within AngularJS

After utilizing AngularJS for a considerable amount of time, I have encountered some challenges with managing data sets.

Imagine having an array of items:

[
 { id: 1, votes: 10, detailInformation: 'Interesting #1' },
 { id: 2, votes: 12, detailInformation: 'Interesting #2' }
]

To keep the user informed with the latest information, I've set a $timer to fetch this data every 60 seconds from a REST webservice.

The presentation of these items to the user is in the following format:

|   ID: {{item.id}}    Votes: {{item.votes}}                                             |
|   <span data-ng-click="item.showInfo = true">Click here to view detail info</span>     |
|   <span data-ng-show="item.showInfo == true">{{item.detailInformation}}</span>         |

Although this setup works well, when the timer updates the content, it resets the view state (item.showInfo = true). How can I effectively manage this client-only state separate from the server data that requires regular updates?

javascript ajax angularjs model

Answer 1

Answer №1

To properly structure your controller, it's important to keep the showInfo function as a separate entity within your code. Avoid including it in the response object received from the server. Instead, define it within your controller like so:

app.controller('test', ['$scope','urService',function($scope,urService){
    $scope.showInfo = true;
    urService.getData(function(data){
       //update data in another scope object
    }
}]);

Answer 2

To properly structure your controller, it's important to keep the showInfo function as a separate entity within your code. Avoid including it in the response object received from the server. Instead, define it within your controller like so:

app.controller('test', ['$scope','urService',function($scope,urService){
    $scope.showInfo = true;
    urService.getData(function(data){
       //update data in another scope object
    }
}]);

Answer 3

Answer №2

In order to optimize performance, I recommend storing item.showInfo on a different reference:

JavaScript:

$http.get('/api/endpoint').then(function (data) {
  $scope.items = data;
  $scope.isShown = new Array(data.length); // initializing $scope.isShown when receiving data for the first time
}

HTML:

<div ng-repeat="item in items">
  <button ng-click="isShown[$index] = true">Click here to view detailed information</button>
  <span ng-show="isShown[$index]">{{ item.detailInformation }}</span>
</div>

Answer 4

In order to optimize performance, I recommend storing item.showInfo on a different reference:

JavaScript:

$http.get('/api/endpoint').then(function (data) {
  $scope.items = data;
  $scope.isShown = new Array(data.length); // initializing $scope.isShown when receiving data for the first time
}

HTML:

<div ng-repeat="item in items">
  <button ng-click="isShown[$index] = true">Click here to view detailed information</button>
  <span ng-show="isShown[$index]">{{ item.detailInformation }}</span>
</div>

Answer 5

Answer №3

Shoutout to V31 for sparking the idea, which I then took and made more adaptable:

// Your controller
$scope.items = [] // Holds data from the webservice
$scope.itemsViewState = {} // Map storing all viewstates with ID as key.

The HTML:

<div ng-repeat="item in items">
    ID: {{item.id}} <br />
    Votes: {{item.votes}} <br />
    <span data-ng-click="itemsViewState[item.id] = true">Click to see details</span> 
    <span data-ng-show="itemsViewState[item.id] == true">{{item.detailInformation}}</span>
</div>

If you need to store multiple properties per object, remember to create a map for each level:

// Your controller
$scope.items = [] // Contains webservice data
$scope.itemsViewState = {} // Map with viewstate by ID.
$scope.openDetail = function($item) { 
$scope.itemsViewState[item.id] = {}; 
$scope.itemsViewState[item.id]['subprop'] = true; }

The HTML:

<div ng-repeat="item in items">
    ID: {{item.id}} <br />
    Votes: {{item.votes}} <br />
    <span data-ng-click="openDetail(item)">Click to see details</span> 
    <span data-ng-show="itemsViewState[item.id]['subprop'] == true">{{item.detailInformation}}</span>
</div>

Answer 6

Shoutout to V31 for sparking the idea, which I then took and made more adaptable:

// Your controller
$scope.items = [] // Holds data from the webservice
$scope.itemsViewState = {} // Map storing all viewstates with ID as key.

The HTML:

<div ng-repeat="item in items">
    ID: {{item.id}} <br />
    Votes: {{item.votes}} <br />
    <span data-ng-click="itemsViewState[item.id] = true">Click to see details</span> 
    <span data-ng-show="itemsViewState[item.id] == true">{{item.detailInformation}}</span>
</div>

If you need to store multiple properties per object, remember to create a map for each level:

// Your controller
$scope.items = [] // Contains webservice data
$scope.itemsViewState = {} // Map with viewstate by ID.
$scope.openDetail = function($item) { 
$scope.itemsViewState[item.id] = {}; 
$scope.itemsViewState[item.id]['subprop'] = true; }

The HTML:

<div ng-repeat="item in items">
    ID: {{item.id}} <br />
    Votes: {{item.votes}} <br />
    <span data-ng-click="openDetail(item)">Click to see details</span> 
    <span data-ng-show="itemsViewState[item.id]['subprop'] == true">{{item.detailInformation}}</span>
</div>

Navigating live data and managing the view state within AngularJS

Answer №1

Answer №2

Answer №3

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