javascript - Where do I need a closure for this one? -

i have constructor:

var editableitem = (function() {      function editableitem(schema, item) {         this.schema = _.clone(schema);         this.item = _.clone(item);         this.propertytypes = [             'stringproperties',             'booleanproperties'];     }      editableitem.prototype = {         createitem: function() {             var self = this;             self.propertytypes.foreach(function(type) {                 var properties = self.schema[type];                 properties.foreach(function(property, i) {                     var itemproperty = self.item[type][property.id];                     if (itemproperty) {                         properties[i].value = itemproperty;                     }                 });             });              self.schema.itemid = self.item._id;              return self.schema;         }     };      return editableitem;  })(); 

and each time use it, this...

async.parallel({     schema: function(callback) {         schemas().findone({             _id: 'default'         }, callback);     },     items: function(callback) {         items().find().toarray(callback);     } },  function(err, result) {     if (err) return callback(err);      var = result.items.map(function(item) {         return new editableitem(result.schema, item).createitem();     });      callback(null, all); }); 

...i end array result last item repeated while others omitted.

my guess need add closure somewhere, , can see i've tried, still yields same result. ideas?

edit: i've found solution. it's not pretty, maybe here can explain why works , offer better solution...

in constructor, had: this.schema = _.clone(schema);

i changed to: this.schema = json.parse(json.stringify(schema));

this seems allocate new memory object, while _.clone still keeps references original object (i guess).

javascript numbers, strings & booleans equated , passed by value while objects , arrays equated , passed by reference. json representation of object string, equated , passed value.

if working json representation of schema gives different behaviour clone (an object), may conclude clone still contains references same objects original, uncloned schema; ie. clone not "deep".

as understand it, underscore.js doesn't yet offer deep clone lo_dash does. might try lo_dash's underscore compatibility build.

alternatively, stick json approach, doing same more formal deep clone method.