Simple SC.AutoResize example.

resizable_button.js

Pharos360.SelectButtonView = SC.SelectButtonView.extend(SC.AutoResize, {
        
  supportsAutoResize: YES,
        
  autoResizeLayer: function() { return this.get('layer') }.property('layer').cacheable(),
  autoResizeText: function() { return this.get('longestChoice') }.property('longestChoice').cacheable(),
        
  needsResize: YES,
        
  longestChoice: "",
  preferMatrix: null,//[3,0,1,2,3],
  changeSelectButtonPreferMatrix: function() {
    /*      
     * Ensure this resizes appropriately with the text.
     */
    if (this.get('needsResize')) {
      var choices = this.get('objects');
      var longestChoice = "";
      
      choices.forEach(function (choice) {
        var rep_id = choice.get('report_identifier');

        if (rep_id.length > longestChoice.length) {
          longestChoice = rep_id;
        } 
      }); 
          
      this.set('longestChoice', longestChoice + "DDDD");
      this.set('needsResize', NO);
    }
  }.observes('needsResize'),
    
  objectsDidChange: function() { 
    this.set('needsResize', YES);
  }.observes('objects')
      
});