linq.js

LINQ for JavaScript.

Info

Archive, import from Codeplex.

I recommend use fork version - mihaifm/linq

Features

implement all .NET 4.0 methods and many extra methods (inspired from Rx, Haskell, Ruby, etc...)
complete lazy evaluation
full IntelliSense support for VisualStudio
two versions - linq.js and jquery.linq.js (jQuery plugin)
support Windows Script Host
binding for Reactive Extensions for JavaScript(RxJS) and IntelliSense Generator -> see [documentation]
NuGet install support - linq.js, linq.js-jQuery, linq.js-Bindings

90 Methods

Aggregate, All, Alternate, Any, Average, BufferWithCount, CascadeBreadthFirst, CascadeDepthFirst, Catch, Choice, Concat, Contains, Count, Cycle, DefaultIfEmpty, Distinct, Do, ElementAt, ElementAtOrDefault, Empty, Except, Finally, First, FirstOrDefault, Flatten, ForEach, Force, From, Generate, GetEnumerator, GroupBy, GroupJoin, IndexOf, Insert, Intersect, Join, Last, LastIndexOf, LastOrDefault, Let, Matches, Max, MaxBy, MemoizeAll, Min, MinBy, OfType, OrderBy, OrderByDescending, Pairwise, PartitionBy, Range, RangeDown, RangeTo, Repeat, RepeatWithFinalize, Return, Reverse, Scan, Select, SelectMany, SequenceEqual, Share, Shuffle, Single, SingleOrDefault, Skip, SkipWhile, Sum, Take, TakeExceptLast, TakeFromLast, TakeWhile, ThenBy, ThenByDescending, ToArray, ToDictionary, ToInfinity,ToJSON, ToLookup, ToNegativeInfinity, ToObject, ToString, Trace, Unfold, Union, Where, Write, WriteLine, Zip

see details - linq.js Reference & LINQPad

Starting linq.js ver.3.0.0-beta!(2012/07/19)

Get v3 branch or NuGet Install-Package linq.js -Pre, linq.js-jQuery -Pre, linq.js-RxJS -Pre, linq.js-QUnit -Pre

All methods becomes lower-camel-case.

Query objects or json

sample from http://twitter.com/statuses/public_timeline.json

var jsonArray = [
    { "user": { "id": 100, "screen_name": "d_linq" }, "text": "to objects" },
    { "user": { "id": 130, "screen_name": "c_bill" }, "text": "g" },
    { "user": { "id": 155, "screen_name": "b_mskk" }, "text": "kabushiki kaisha" },
    { "user": { "id": 301, "screen_name": "a_xbox" }, "text": "halo reach" }
]
// ["b_mskk:kabushiki kaisha", "c_bill:g", "d_linq:to objects"]
var queryResult = Enumerable.From(jsonArray)
    .Where(function (x) { return x.user.id < 200 })
    .OrderBy(function (x) { return x.user.screen_name })
    .Select(function (x) { return x.user.screen_name + ':' + x.text })
    .ToArray();
// shortcut! string lambda selector
var queryResult2 = Enumerable.From(jsonArray)
    .Where("$.user.id < 200")
    .OrderBy("$.user.screen_name")
    .Select("$.user.screen_name + ':' + $.text")
    .ToArray();

High compatibility with C# Linq

// C# LINQ (delegate)
Enumerable.Range(1, 10)
    .Where(delegate(int i) { return i % 3 == 0; })
    .Select(delegate(int i) { return i * 10; });
// linq.js - anonymous function
Enumerable.Range(1, 10)
    .Where(function(i) { return i % 3 == 0; })
    .Select(function(i) { return i * 10; });
// C# LINQ (lambda)
Enumerable.Range(1, 10).Where(i => i % 3 == 0).Select(i => i * 10);
// linq.js - lambda expression
Enumerable.Range(1, 10).Where("i => i % 3 == 0").Select("i => i * 10");
// $ is default iterator variable like Scala's "_" or Groovy's "it"
Enumerable.Range(1, 10).Where("$ % 3 == 0").Select("$ * 10");
 // "" is shorthand of "x => x" (identity function)
Enumerable.Range(4, 7).Join(Enumerable.Range(8, 5), "", "", "outer,inner=>outer*inner");

// Enumerable.From is wrap from primitive array, string(to charArray), object(to KeyValuePair[]) etc..
var array = [100, 200, 30, 40, 500, 40, 200];
var ex1 = Enumerable.From(array).Distinct().ToArray(); // [100, 200, 30, 40, 500]
var ex2 = Enumerable.From("foobar").ToArray(); // ["f", "o", "o", "b", "a", "r"];
var ex3 = Enumerable.From({foo:10, bar:20}).ToArray(); // [{Key:"foo",Value:10}, {Key:"bar",Value:20}]

// C# - AnonymousType
array.Select((val, i) => new { Value = val, Index = i });
// linq.js - object literal
Enumerable.From(array).Select("val,i=>{Value:val, Index:i}")

jQuery plugin version

// $.Enumerable
$.Enumerable.Range(1, 10).Where("$%2==0").ForEach("alert($)");

// TojQuery - Enumerable to jQuery
$.Enumerable.Range(1, 10)
    .Select(function (i) { return $("<option>").text(i)[0] })
    .TojQuery()
    .appendTo("#select1");

// toEnumerable - jQuery to Enumerable
var sum = $("#select1").children()
    .toEnumerable()
    .Select("parseInt($.text())")
    .Sum(); // 55

IntelliSense vsdoc

with Windows Script Host

// get folder name and file name...

var dir = WScript.CreateObject("Scripting.FileSystemObject").GetFolder("C:\\");
 
// normally
var itemNames = [];
for (var e = new Enumerator(dir.SubFolders); !e.atEnd(); e.moveNext())
{
    itemNames.push(e.item().Name);
}
for (var e = new Enumerator(dir.Files); !e.atEnd(); e.moveNext())
{
    itemNames.push(e.item().Name);
}

// linq.js
var itemNames2 = Enumerable.From(dir.SubFolders).Concat(dir.Files).Select("$.Name").ToArray();

flyingfive/linq.js