linq

library0.3.1jsnpmunverified

Linq.js is a comprehensive JavaScript implementation of the .NET Language Integrated Query (LINQ) library, offering a fluent API for querying and manipulating data collections. It includes all the original .NET LINQ methods along with several additions, enabling powerful data transformations and filtering across various iterable objects like arrays, Maps, and Sets. The current stable version is 4.0.3, with a release cadence that has provided incremental updates for improved iteration protocol support and enhanced TypeScript definitions. A key differentiator is its transition to a pure ES module structure in version 4.0.0, making it fully compatible with modern JavaScript environments such as Node.js (v14.13.1 and later), TypeScript projects, Deno, and contemporary web browsers. For projects requiring CommonJS modules or targeting older environments, version 3 of the library remains available.

data serialization

npm install linq

github ↗package ↗

INSTALL

IMPORT

SIG · LINQ

linq

datajavascriptv0.3.1

Install

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Import

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Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Enumerable

✓ import Enumerable from 'linq'

✗ const Enumerable = require('linq')

The library is an ES module since v4.0.0. CommonJS 'require' syntax will fail; use 'linq@3' for CJS projects.

IEnumerable<T>

✓ import Enumerable from 'linq'; type MyCollection = Enumerable.IEnumerable<number>;

✗ import { IEnumerable } from 'linq'

IEnumerable is a type available via the default 'Enumerable' import, not a named export itself.

Enumerable (CommonJS)

✓ const Enumerable = require('linq')

✗ import Enumerable from 'linq'

This import pattern is only correct for linq@3 and earlier versions. linq@4+ is ESM-only.

Demonstrates basic LINQ operations including filtering, mapping, and querying iterable objects like Maps, highlighting its fluent API.

// For Node.js (v14.13.1+) with "type": "module" in package.json import Enumerable from 'linq'; // Example 1: Basic filtering and transformation let result1 = Enumerable.range(1, 10) .where(i => i % 3 === 0) .select(i => i * 10) .toArray(); console.log('Filtered and multiplied:', result1); // [ 30, 60, 90 ] // Example 2: Working with objects and iterating over Map/Set const data = new Map([ ['apple', 10], ['banana', 20], ['cherry', 30] ]); let result2 = Enumerable.from(data) .where(([key, value]) => value > 15) .select(([key, value]) => ({ fruit: key, quantity: value * 2 })) .toArray(); console.log('Querying Map:', result2); // [ { fruit: 'banana', quantity: 40 }, { fruit: 'cherry', quantity: 60 } ] // Example 3: Finding the first element meeting a condition let firstBigRadius = Enumerable.toInfinity(1) .where(r => r * r * Math.PI > 10000) .first(); console.log('First radius for area > 10000:', firstBigRadius);

Debug

Known issues

breakingVersion 4.0.0 fully transitioned to an ES module (ESM) architecture, deprecating CommonJS (CJS) support for the current major release. This means `require()` syntax is no longer supported with `linq@4` and newer.

fix

For new projects, ensure your Node.js environment is v14.13.1+ and your `package.json` includes `'type': 'module'`. For existing CommonJS projects, continue using `npm install linq@3`.

affects: >=4.0.0

gotchaAttempting to use `linq@4` or newer in a Node.js project without configuring it as an ES module will result in module resolution errors. This is typically indicated by a `SyntaxError: Cannot use import statement outside a module`.

fix

Add `'type': 'module'` to your `package.json` file to enable ES module resolution. Alternatively, rename your `.js` files to `.mjs` or use `linq@3` for CommonJS.

affects: >=4.0.0

gotchaThe library ships with TypeScript definitions, but correct usage requires specific `tsconfig.json` compiler options, particularly `target` set to `ES2020` or higher and `moduleResolution` to `node`.

fix

Configure your `tsconfig.json` with `{'compilerOptions': {'target': 'ES2020', 'moduleResolution': 'node'}}` to ensure types are correctly resolved and compiled.

affects: >=4.0.0

gotchaVersion 3.2.3 introduced `Enumerable.Utils.recallFrom` which implies that `Enumerable.Utils.extendTo` (for prototype pollution) should be used with extreme caution, as direct prototype extension is generally discouraged in modern JavaScript.

fix

Avoid using `Enumerable.Utils.extendTo` to modify built-in prototypes. Prefer direct instantiation with `Enumerable.from()` or method chaining on `Enumerable` directly to avoid global object mutation.

affects: *

Errors

Common errors & fixes

SyntaxError: Cannot use import statement outside a module

Attempting to use ES module `import` syntax for `linq@4+` in a CommonJS Node.js project.

fix

Add `'type': 'module'` to your `package.json` or switch to `linq@3` and use `const Enumerable = require('linq')`.

ReferenceError: Enumerable is not defined

Using `require('linq')` with `linq@4+` in a Node.js ES module project, or in an environment where the global `Enumerable` is not exposed (e.g., modern browser without `<script type='module'>`).

fix

For `linq@4+`, use `import Enumerable from 'linq'` in an ES module project. For CommonJS, use `linq@3` and `const Enumerable = require('linq')`.

TypeError: 'Enumerable' is not a constructor

The `Enumerable` object is a singleton or a static class-like object, not a constructor. It is meant to be used with static methods like `Enumerable.range()` or `Enumerable.from()`.

fix

Do not attempt to instantiate `Enumerable` with `new`. Call its static methods directly, e.g., `Enumerable.range(1, 10)` or `Enumerable.from(myArray)`.

TS2305: Module '"linq"' has no exported member 'IEnumerable'.

`IEnumerable` is a type available via the default `Enumerable` import, not a named export itself, or `tsconfig.json` is not configured correctly.

fix

Import `Enumerable` as a default import and then use `Enumerable.IEnumerable<T>` for type annotation: `import Enumerable from 'linq'; type MyType = Enumerable.IEnumerable<string>;`. Ensure `tsconfig.json` includes `{'compilerOptions': {'target': 'ES2020', 'moduleResolution': 'node'}}`.

Upgrade

Version history

0.3.1latest on npm

Audit

Dependencies

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Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/mihaifm/linq ↗

packagehttps://www.npmjs.com/package/linq ↗