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This is a JavaScript implementation of the .NET LINQ library.

It contains all the original .NET methods plus a few additions.

Written in pure JavaScript with no dependencies.


// 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 - arrow function
Enumerable.range(1, 10).where((i) => i % 3 == 0).select((i) => i * 10);
// C# LINQ - anonymous type
array.Select((val, i) => new { Value: val, Index: i }());

// linq.js - object literal
Enumerable.from(array).select((val, i) => ({ value: val, index: i }));

See sample/tutorial.js and the test folder for more examples.


Node.js (ES modules)

Install the latest version of the library with npm:

npm install linq

Load it in your code with the import syntax:

import Enumerable from 'linq'

let result = Enumerable.range(1, 10).where(i => i % 3 == 0).select(i => i * 10)
console.log(result.toArray()) // [ 30, 60, 90 ]

Because the library is an ES module, this code will only work if your project is also configured as an ES module. Add the following line in your package.json to make it an ES module:

"type": "module"

If you're not planning to use ES modules, check the CommonJS section below.

Node.js (CommonJS modules)

Install version 3 of this library:

npm install linq@3

Load it with the require syntax:

const Enumerable = require('linq')

let count = Enumerable.range(1, 10).count(i => i < 5)
console.log(count) // 4

The cjs branch contains the source code for the CommonJS version of the library.


Install the latest version of the library with npm.

Configure your compiler options in tsconfig.json

"compilerOptions": {
    "target": "ES2020",
    "moduleResolution": "node"

The library comes with a d.ts file containing type definitions for all the objects and methods, feel free to use them in your code:

import Enumerable from 'linq';

type tnum = Enumerable.IEnumerable<number>;
let x: tnum = Enumerable.from([1, 2, 3]);


Import the library from Use the @deno-types annotation to load type definitions:

// @deno-types=""
import Enumerable from ''

let radius = Enumerable.toInfinity(1).where(r => r * r * Math.PI > 10000).first()

You can also install locally with npm. Use the full file path when importing the library:

// @deno-types="./node_modules/linq/linq.d.ts"
import Enumerable from './node_modules/linq/linq.js'


The minified version of the library is available in the release archive.

Load it via <script type="module">:

<script type="module" src="./linq.min.js"></script>
<script type="module">
    import Enumerable from './linq.min.js'
    Enumerable.from([1, 2, 3]).forEach(x => console.log(x))

You can also load the library via a CDN:



Yoshifumi Kawai developed the original version of this library.


MIT License