如何在angularjs应用程序中包含全局变量？

Question

I have a global variable declared outside of angular context:

var globalv = "Hello";

This variable does not change. I have a directive that wants to use it...

$scope.somevar = globalv + "_";

What is the simplest way to include the globalv in my angularjs app/context? When I attempt to reference it in the above manner, I get an error.

Answer 1

I would consider wrapping the value in an angular constant which will enable you to inject it only where its needed

var myApp = angular.module('myApplication',[]);
myApp.constant('myConstant', globalv);

Just ensure that the globalv variable is defined before your angular module is defined.

I like this better than using a rootscope/global variable since you can control who the consumers of the value are.

You can inject the constant like so:

mayApp.directive('myDirective',['myConstant',
        function (myConstant) {
            return {
                ..
        };
}]);

Answer 2

Is there any reason why you couldn't include it in the angular context? If it absolutely needs to be global you can add it to the rootscope within the angular context.

/* declare rootscope variables when the angular app starts*/
angular.module('someApp').run(function ($rootScope) {
    $rootscope.globalv = "Hello";
});

You can then reference that rootscope variable anywhere within your angular app.

This is pretty simple to me, but I personally hate using $rootScope unless I have to. You should really try and get away from global variables.