Pattern for executing Breeze Queries in angularjs project - angularjs

Question

I am attempting to come up with a generic function to execute a breeze query. The objectives of this function are:
To first check if the query has been previously executed. If so, execute the query locally.
To work in environments such as Sharepoint 2013 where the max number of records returned are limited to 100 (in most cases).
I have been able to write the function below (in typescript) and it is generally working. I am storing a variable on the rootscope to indicate if a query has been executed. The main issue I am facing is, I need a generic way of uniquely identifying a query (something like getHashcode in .Net) to store in the rootscope. I am currently using query.resourceName which is not unique enough. Also, do you have any suggestions to improve this function?
execQuery(query: breeze.EntityQuery): ng.IPromise<breeze.Entity[]>
{
var self = this;
var pageNumber = 1;
var pageSize = 100;
var retVal: breeze.Entity[] = [];
var deferred = this.$q.defer();
if (self.$rootScope.queriesExecuted[query.resourceName] == null)
{
query.queryOptions = new breeze.QueryOptions({
fetchStrategy: breeze.FetchStrategy.FromServer,
mergeStrategy: breeze.MergeStrategy.PreserveChanges
});
}
else
{
query.queryOptions = new breeze.QueryOptions({ fetchStrategy: breeze.FetchStrategy.FromLocalCache });
}
__execQuery(query);
function __execQuery(query: breeze.EntityQuery)
{
var pagedQuery = query.skip((pageNumber - 1) * pageSize);
pagedQuery.execute()
.then(function (data)
{
self.$rootScope.queriesExecuted[query.resourceName] = true;
$.merge(retVal, data.results);
pageNumber++;
if (data.results.length == pageSize)
{
__execQuery(query);
}
else
{
deferred.resolve(retVal);
}
});
}
return deferred.promise;
}

Answer 1

EntityQuery has a "protected" (undocumented and not future-proof) function, _toUri(metadataStore), which returns the URI serialization of the resource name and all the query parameters. That will be the unique identifier that you seek. It requires the MetadataStore, which you can get from the EntityManager.