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var myModule = angular.module('ExampleApp', []);

myModule.constant('CONSTANTS', (function () {
    var constants = {};
    
    constants.VERSION = '1.2.3';
    
    constants.URL = 'http://www.example.com/' + constants.VERSION + '/';
    
    constants.API_URL = 'http://api.example.com/' + constants.VERSION + '/';
    
    return constants;
}()));

myModule.controller('DemoController', 
    function (CONSTANTS, $scope) {
        $scope.constants = JSON.stringify(CONSTANTS, null, 2);
    });

<div ng-app="ExampleApp">
    <div ng-controller="DemoController">
        <pre>
Constants: {{constants}}
        </pre>
    </div>
</div>