在JavaScript中使用LINQ：linq.js插件簡介

功能

• 實現所有.NET 4.0的方法和許多額外的方法

• 完成懶惰評估

• 全面的IntelliSense支持VisualStudio

• 兩個版本 - linq.js和jquery.linq.js（jQuery插件）

• 支持Windows Script Host

• 綁定用於JavaScript（RxJS）和IntelliSense Generator的反向擴展

• NuGet安裝支持（linq.js， linq.js-jQuery， linq.js-Bindings）

90多個個方法

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

使用linq.js ver.3.0.0

NuGet Install-Package linq.js -Pre，linq.js-jQuery -Pre，linq.js-RxJS -Pre，linq.js-QUnit -Pre

Now TypeScript泛型支持

查詢對象或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();

與C＃Linq兼容性高

// 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插件版本

// $.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

與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();