Extended schema-validate directive to handle cleaning the model when a form field element triggers the $destroy. Uses a new service, based on Select, to traverse the model and update it to the value chosen as part of the configured destroyStrategy. This destroyStrategy can be configured at the field, or as part of the forms global options. If both are defined, the field-level strategy will override.

Author: jbsaff

docs/index.md

@@ -634,6 +634,7 @@ General options most field types can handle:
   labelHtmlClass: "street"     // CSS Class(es) to be added to the label of the field (or similar)
   copyValueTo: ["address.street"],     // Copy values to these schema keys.
   condition: "person.age < 18" // Show or hide field depending on an angular expression
+  destroyStrategy: ''          // Update the model when the field is destoyed, e.g. when condition is not longer satisfied.
 }
 ```
 
@@ -823,6 +824,14 @@ function FormCtrl($scope) {
 Note that arrays inside arrays won't work with conditions.
 
 
+### destroyStrategy
+By default, when a field is removed from the DOM and the $destroy event is broadcast, the schema-validate directive 
+will update the model to set the field value to undefined. This can be overridden by setting the destroyStrategy 
+on a field to one of null, empty string (""), undefined, or "retain". Any other value will be ignored and the default  
+behavior will apply. The empty string option only applies to fields that have a type of string; using the empty string 
+with other field types will just be set to the default destroyStrategy. If you'd like to set the destroyStrategy for 
+an entire form, add it to the formDefaults in the [globalOptions](#global-options)
+
 
 
 Specific options and types

src/directives/schema-validate.js

@@ -1,4 +1,6 @@
-angular.module('schemaForm').directive('schemaValidate', ['sfValidator', 'sfSelect', function(sfValidator, sfSelect) {
+angular.module('schemaForm').directive('schemaValidate', ['sfValidator', 'sfSelect', 'sfUnselect',
+  function(sfValidator, sfSelect, sfUnselect) {
+
   return {
     restrict: 'A',
     scope: false,
@@ -8,7 +10,6 @@ angular.module('schemaForm').directive('schemaValidate', ['sfValidator', 'sfSele
     require: 'ngModel',
     link: function(scope, element, attrs, ngModel) {
 
-
       // We need the ngModelController on several places,
       // most notably for errors.
       // So we emit it up to the decorator directive so it can put it on scope.
@@ -101,6 +102,68 @@ angular.module('schemaForm').directive('schemaValidate', ['sfValidator', 'sfSele
 
       });
 
+
+      var DEFAULT_DESTROY_STRATEGY;
+      if (scope.options && scope.options.formDefaults) {
+        var formDefaultDestroyStrategy = scope.options.formDefaults.destroyStrategy;
+        var isValidFormDefaultDestroyStrategy = (formDefaultDestroyStrategy === undefined ||
+        formDefaultDestroyStrategy === '' ||
+        formDefaultDestroyStrategy === null ||
+        formDefaultDestroyStrategy === 'retain');
+        if (isValidFormDefaultDestroyStrategy) {
+          DEFAULT_DESTROY_STRATEGY = formDefaultDestroyStrategy;
+        }
+        else {
+          console.warn('Unrecognized formDefaults.destroyStrategy: \'%s\'. Used undefined instead.',
+              formDefaultDestroyStrategy);
+          DEFAULT_DESTROY_STRATEGY = undefined;
+        }
+      }
+
+      // Clean up the model when the corresponding form field is $destroy-ed.
+      // Default behavior can be supplied as a formDefault, and behavior can be overridden in the form definition.
+      scope.$on('$destroy', function() {
+        var form = getForm();
+        var destroyStrategy = form.destroyStrategy; // Either set in form definition, or as part of formDefaults.
+        var schemaType = getSchemaType();
+
+        if (destroyStrategy && destroyStrategy !== 'retain' ) {
+          // Don't recognize the strategy, so give a warning.
+          console.warn('Unrecognized destroyStrategy: \'%s\'. Used default instead.', destroyStrategy);
+          destroyStrategy = DEFAULT_DESTROY_STRATEGY;
+        }
+        else if (schemaType !== 'string' && destroyStrategy === '') {
+          // Only 'string' type fields can have an empty string value as a valid option.
+          console.warn('Attempted to use empty string destroyStrategy on non-string form type. Used default instead.');
+          destroyStrategy = DEFAULT_DESTROY_STRATEGY;
+        }
+
+        if (destroyStrategy === 'retain') {
+          return; // Valid option to avoid destroying data in the model.
+        }
+
+        destroyUsingStrategy(destroyStrategy);
+
+        function destroyUsingStrategy(strategy) {
+          var strategyIsDefined = (strategy === null || strategy === '' || typeof strategy == undefined);
+          if (!strategyIsDefined){
+            strategy = DEFAULT_DESTROY_STRATEGY;
+          }
+          sfUnselect(scope.form.key, scope.model, strategy);
+        }
+
+        function getSchemaType() {
+          if (form.schema) {
+            schemaType = form.schema.type;
+          }
+          else {
+            schemaType = null;
+          }
+        }
+      });
+
+
+
       scope.schemaError = function() {
         return error;
       };

src/services/unselect.js

@@ -0,0 +1,83 @@
+
+angular.module('schemaForm').factory('sfUnselect', ['sfPath', function(sfPath) {
+  var numRe = /^\d+$/;
+
+  /**
+   * @description
+   * Utility method to clear deep properties without
+   * throwing errors when things are not defined.
+   * DOES NOT create objects when they are missing.
+   *
+   * Based on sfSelect.
+   *
+   * ex.
+   * var foo = Unselect('address.contact.name',obj, null)
+   * var bar = Unselect('address.contact.name',obj, undefined)
+   * Unselect('address.contact.name',obj,'')
+   *
+   * @param {string} projection A dot path to the property you want to set
+   * @param {object} obj   (optional) The object to project on, defaults to 'this'
+   * @param {Any}    unselectValue   The value to set; if parts of the path of
+   *                 the projection is missing empty objects will NOT be created.
+   * @returns {Any|undefined} returns the value at the end of the projection path
+   *                          or undefined if there is none.
+   */
+  return function(projection, obj, unselectValue) {
+    if (!obj) {
+      obj = this;
+    }
+    //Support [] array syntax
+    var parts = typeof projection === 'string' ? sfPath.parse(projection) : projection;
+    //console.log(parts);
+
+    if (parts.length === 1) {
+      //Special case, just setting one variable
+
+      //console.log('Only 1 variable in parts');
+      obj[parts[0]] = unselectValue;
+      return obj;
+    }
+
+    if (typeof obj[parts[0]] === 'undefined') {
+      // If top-level part isn't defined.
+      var isArray = numRe.test(parts[1]);
+      if (isArray) {
+        //console.info('Expected array as top-level part, but is already undefined. Returning.');
+        return undefined;
+      }
+      else if (parts.length > 2) {
+        obj[parts[0]] = {};
+      }
+    }
+
+    var value = obj[parts[0]];
+    for (var i = 1; i < parts.length; i++) {
+      // Special case: We allow JSON Form syntax for arrays using empty brackets
+      // These will of course not work here so we exit if they are found.
+      if (parts[i] === '') {
+        return undefined;
+      }
+
+      var tmp = value[parts[i]];
+      if (i === parts.length - 1 ) {
+        //End of projection; setting the value
+
+        //console.log('Value set using destroyStrategy.');
+        value[parts[i]] = unselectValue;
+        return unselectValue;
+      } else {
+        // Make sure to NOT create new objects on the way if they are not there.
+        // We need to look ahead to check if array is appropriate.
+        // Believe that if an array/object isn't present/defined, we can return.
+
+        //console.log('Processing part %s', parts[i]);
+        if (typeof tmp === 'undefined' || tmp === null) {
+          //console.log('Part is undefined; returning.');
+          return undefined;
+        }
+        value = tmp;
+      }
+    }
+    return value;
+  };
+}]);