linq js

In JavaScript (even with other framework library), there may not be some very easy dot notation way to filter data.

You often have to go through the whole collection then to push values into another array object to collect the values that you want, filtering. 

Data Structure

[ FieldName : string, Filters :  [ IsSelected : boolean, Value : variant  ] ]

Typical JavaScript Filtering Pattern

var data = fetchData(); // gets the ajax data in Json array

var filteredData = new Array(); // where new filtered 

var filterListLimit = getFilteredListLimit(); // number of times which the category changes

/// this is O(n^2) ~= f(x) = O * nO 

for (var q = 0; q < data.length; q++) {

var oX = data[q]; // for convenience

var includeCounter = 0;

for (var f = 0; f < FilterList.length; f++) {

if (oX[FilterList[f][0]] == FilterList[f][1]) {

includeCounter++;

}

}

if (includeCounter == filterListLimit) {

filteredData.push(oX);

}

}

In C#, you can do 

var filteredData =( from p in data

where p.key == 5

select new {

   Brand = p.Brand,

   Name = p.Name,

   Year = new DateTime(p.Date).Year

}).Distinct();

with linq.js, you can do

var filteredData = Enumerable.From(data)

.Where(function(x) { return ( x.key == 5 ) })

.Select("o=> { Brand : o.Brand, Name : o.Name, Year : o.Year "}).Distinct().ToArray();

Neat ... :-)

There are more examples and a file at the below link.

http://linqjs.codeplex.com/