Linq

This gem is wrapper for linq.js JavaScript plugin. Language-Integrated Query (LINQ) is a set of features introduced in Visual Studio 2008 (That moment for #C, VisualBasic) that extends powerful query capabilities to the language syntax. LINQ introduces standard, easily-learned patterns for querying and updating data, and the technology can be extended to support potentially any kind of data store.

Features

• Implement all .NET 4.0 methods and many extra methods (inspiration from Rx, Achiral, Haskell, Ruby, etc...)
• Complete lazy evaluation
• Two versions - linq.js and jquery.linq.js (jQuery plugin)
• Binding for Reactive Extensions for JavaScript(RxJS)

Installation

Add this line to your application's Gemfile:

gem 'linq'

And then execute:

$ bundle

Or install it yourself as:

$ gem install linq

Add to javascript manifest application.js

//= require linq

Examples of usage

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" }
]

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();

More tricky:

// anonymous function
Enumerable.Range(1, 10)
    .Where(function(i) { return i % 3 == 0; })
    .Select(function(i) { return i * 10; });
    
// 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}]

// object literal
Enumerable.From(array).Select("val,i=>{Value:val, Index:i}")

And Jquery:

// $.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

Full documentation is on the wiki