AngularJS, how to bind a variable to concatenation of two other bound variables?

Question

I am new to AngularJS and trying to build an AngularJS practice app, in which, the user will concatenate a url from multiple inputs, i.e. protocol, domain, path, param1, param2,

Answer 1

Another similar approach is to use ng-init directive to create a dynamic property which represents the concatenation of all those properties. You can call the function or just concatenate inline.

 <a ng-init="urlParts.url=makeUrl()" 
ng-href="urlParts.url">{{urlParts.url}}
</a>

<a ng-init="urlParts.url=urlParts.protocol + '://' + $scope.urlParts.domain..." 
    ng-href="urlParts.url">{{urlParts.url}}
    </a>

Reference: http://www.ozkary.com/2015/03/angularjs-ng-model-concatenate-model.html

Try It: http://plnkr.co/edit/PSvwCE?p=info

Answer 2

Just use this binding expression to concatenation of more than two scope variables in HTML.

{{UserData.FirstName + ' ' + UserData.MiddleName + ' ' + UserData.LastName}}

If you want to do this inside any attribute, Just write like this:

<input type="text" ng-value="UserData.FirstName + ' ' + UserData.MiddleName + ' ' + UserData.LastName">

Answer 3

You shouldn't assign scope variables in the view (the HTML) - it's only for reading them.

To make a new variable from inputs, add a ng-model to each of them and then in the controller define a method that makes a $scope variable from them e.g.

Your HTML form:

<div ng-controller="MyCtrl">

    <input type="text" ng-model="urlParts.protocol">
    <input type="text" ng-model="urlParts.domain">
    <!-- etc -->
    <a ng-href="{{makeUrl()}}">{{makeUrl()}}</a>
</div>

JS:

function MyCtrl($scope) {
    $scope.urlParts = {};
    $scope.urlParts.protocol = ""; 
    $scope.urlParts.domain = ""; 
    // etc... 
    // These values will be updated when the user types in the input boxes

    $scope.makeUrl = function() {
      return $scope.urlParts.protocol + "://" + $scope.urlParts.domain + $scope.urlParts.path + "?" + $scope.urlParts.param1 + "&" + $scope.urlParts.param2 + "&" + $scope.urlParts.param3;
    }
}

Answer 4

If you want to bind a dynamic url with href then you can manipulate you URL in ng-click or ng-mousedown event and bind to target element.

JS:

var goToLinkedPage = function (event, basePath, param1, param2, param 3) {
    var newState = basePath + "?" + param1 + "&" + param2 + "&" + param3;
    jQuery(event.target).attr('href',newState);
};

HTML:

<a ng-mousedown="goToLinkedPage($event, basePath, param1, param2, param3)"> Click Here </a>