code: function iterate(iterator, callback) {
  	        var self = this;
  
  	        var promise = self.ready().then(function () {
  	            var dbInfo = self._dbInfo;
  	            var keyPrefix = dbInfo.keyPrefix;
  	            var keyPrefixLength = keyPrefix.length;
  	            var length = localStorage.length;
  
  	            // We use a dedicated iterator instead of the `i` variable below
  	            // so other keys we fetch in localStorage aren't counted in
  	            // the `iterationNumber` argument passed to the `iterate()`
  	            // callback.
  	            //
  	            // See: github.com/mozilla/localForage/pull/435#discussion_r38061530
  	            var iterationNumber = 1;
  
  	            for (var i = 0; i < length; i++) {
  	                var key = localStorage.key(i);
  	                if (key.indexOf(keyPrefix) !== 0) {
  	                    continue;
  	                }
  	                var value = localStorage.getItem(key);
  
  	                // If a result was found, parse it from the serialized
  	                // string into a JS object. If result isn't truthy, the
  	                // key is likely undefined and we'll pass it straight
  	                // to the iterator.
  	                if (value) {
  	                    value = dbInfo.serializer.deserialize(value);
  	                }
  
  	                value = iterator(value, key.substring(keyPrefixLength), iterationNumber++);
  
  	                if (value !== void 0) {
  	                    return value;
  	                }
  	            }
  	        });
  
  	        executeCallback(promise, callback);
  	        return promise;
  	    }
docs: Iterate over all items in the store.