Angular.js ng-switch ---testing if value is empty or undefined

Question

In Angular.js templating, I need to test if a value is undefined or empty.... I am not sure how to do this since ng-switch-when tests for expressions in strings. I

Answer 1

Following solution would also work (using angular 1.3.10):

<div ng-switch="selection">
    <div ng-switch-default>The string is not empty!</div>
    <div ng-switch-when="undefined">The string is empty!</div>
</div>

Answer 2

<div ng-switch="!!selection">
   <div ng-switch-when="false">Empty, Null or undefined</div>
   <div ng-switch-when="true">The string is not empty</div>
</div>

Answer 3

ng-switch allows expressions, you can use placeholder, as such:

<div ng-switch="selection || '_undefined_'" >      
      <span ng-switch-when="_undefined_">I am set to zero or undefined?!</span>      
      <span ng-switch-default>This string is not empty</span>
</div>

For more info: ng-switch on empty string

You usually do it within controller(see answer#1 in linked thread).