I want to expose to all my views some app-level config value. What is more elegant way to achieve this? Should I declare some app-level controller on `<body>` element and on expose my value using `$scope.myVal = myVal`. Or better to use `rootScope` for this purpose? 

Also in context of this question I want to ask following: is it good practice in AngularJS to exclude to view some simple logic, like building `src` attribute of `img` tag: 

```
<img src="{{config.imagesBaseUrl}}{{product.imageFileName}}"

```

or better to do this concatenation of URL in controller?