LInQer ports .NET LINQ to Javascript

LinQer is a library that sprang out of the need to fix two problems of Javascript's built-in iteration methods. It brings .NET's LINQ approach to databases to JavaScript.

The problems with the iteration methods that needed fixing were mainly that:

• they are applicable to arrays only

and that 

they are eager,meaning that the set undergoing intermittent transformations is the full one,even when only a few items are needed from it:

"Every time you filter or you map something you create a new array".

full article on i-programmer