AngularJS – How to Pass Parameters to Controllers on Initialization

The article presents quick concepts and code samples on how one could pass the parameters to the controller during bootstrapping process. Feel free to comment/suggest.

Usecase: Edit Page to Populate Data Retrieved from Server

I came across a use case where I had to edit an existing object. Thus, I was required to populate the input fields with the existing value. When I tried to do in the usual manner which is like retrieving the object from the server and updating each of the input fields with the right value, it didn’t work out. The input fields were not getting the value retrieved from the server. This is primarily because the model values were initialized with default values when ng-app bootstrapped and controller intialization assigned the default values to model that were bound to input field.

After some research, I figured out that there is a way out to achieve above objective of assigning input fields value with value retrieved from the server. It can be done using “ng-init” call. Following are the steps:

Define an init function in your controller such as following:

helloApp.controller( "HellCtrl", ['$scope', function( $scope ) {

 this.initialize = function( fname, lname, age ) {
     this.firstName = fname;
     this.lastName = lname;
     this.age = age;
 }

}]);

Attach ng-init directive to the element which consists of ng-controller in the following manner. In the example below, fnameStr, lnameStr and ageStr represents the variable that consists of actual value retrieved from the server.

<div ng-controller="HelloCtrl as hctrl" ng-init="hctrl.initialize(fnameStr,lnameStr,ageStr)"></div>

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