Allow angular code in Field.helpText

Author: RichardBradley

src/javascripts/ng-admin/Crud/misc/maHelpText.js

@@ -2,19 +2,31 @@
  * Help text for a form field.
  *
  * @example <ma-help-text field="field"></ma-help-text>
+ *
+ * @param field.helpText()  If a string, it will be displayed as text to the user.
+ *                          If an `angular.element`, it will be compiled and displayed.
+ *                          You can use "entry.values[x]" to check the current value
+ *                          of property "x" (e.g. if you want to give different hints)
  */
-export default function maHelpText() {
+export default function maHelpText($compile) {
     return {
-        scope: {
-            'field': '&'
-        },
+        scope: true,
         restrict: 'E',
         link: function(scope, element) {
-            var field = scope.field();
-            scope.helpText = field.helpText();
+            var field = scope.field;
+
+            var helpText = field && field.helpText();
+            if (helpText && typeof helpText === "object" && helpText.contents) {
+                // looks like an angular.element:
+                element.append(helpText.clone());
+                $compile(element.contents())(scope);
+            } else {
+                // treat as plain text:
+                scope.helpText = helpText;
+            }
         },
         template: '<small ng-if="helpText" class="help-block">{{ helpText }}</small>'
     };
 }
 
-maHelpText.$inject = [];
+maHelpText.$inject = ['$compile'];