moyal.js.linq

A lightweight, zero-dependency JavaScript library that brings LINQ-style querying capabilities to native arrays. Designed for both clarity and performance, it offers a fluent, chainable API for filtering, projecting, grouping, ordering, and aggregating data—without relying on external frameworks.

Information

Current Version: 1.0.4
Author: Ilan Moyal
Website: https://www.moyal.es
License: MIT
NPM: https://www.npmjs.com/package/@moyal/js-linq
API Documentation: View online

Installation
Importing
Features
Quick Start
API Overview
Version Access
Example files and test files
License
Author

Installation

npm install @moyal/js-linq

Importing

In Node.js (ES Module)

import { Linq } from "@moyal/js-linq";

In Node.js (CommonJS)

const { Linq } = require("@moyal/js-linq");

In the Browser (ES Module via CDN)

<!-- From jsDelivr CDN (minified version) -->
<script type="module">
  import "https://cdn.jsdelivr.net/npm/@moyal/js-linq@1.0.4/dist/moyal.linq.umd.min.js";
</script>

<!-- From jsDelivr CDN (non minified version with documentation) -->
<script type="module">
  import "https://cdn.jsdelivr.net/npm/@moyal/js-linq@1.0.4/dist/moyal.linq.umd.js";
</script>

Or using unpkg:

<script type="module">
  import "https://unpkg.com/@moyal/js-linq@1.0.4/dist/moyal.linq.umd.min.js";
</script>

Features

Fully Chainable: Every operation returns a LINQ-like wrapper to continue your query seamlessly.
Deferred Execution: Most operations are lazily evaluated using generators.
Zero Dependencies: No third-party libraries required. Works in both Node.js and browsers.
Rich Set of Operators: Includes filtering, projection, ordering, joining, grouping, set operations, aggregation, and statistics.
Built-in Statistics: Easily compute count, sum, average, median, mode, variance, and standard deviation.
Extensible Comparers & Selectors: All key-based operations support custom comparison and projection logic.
Supports thisArg Binding: Pass custom context for user-defined callbacks.
Typed Statistics API: Strongly encapsulated results with .clone(), .equal(), and .toJSON() support.

Quick Start

import { Linq } from '@moyal/js-linq';

const numbers = [1, 2, 3, 4, 5, 6];

const result = Linq
    .from(numbers)
    .where(x => x % 2 === 0)
    .select(x => x * 10)
    .toArray();

console.log(result); // Output: [20, 40, 60]

/*

In this quick start example:

- We filter out odd numbers.
- We multiply each number in 10.
- Dumping the result iterable to array.

*/

For more code examples, see also "/examples" and (or) "/test/units" in GitHub Repository.

API Overview

Method / Static	Purpose
`from(iter)`	Start LINQ chain from iterable
`aggregate(seed, fn)`	Accumulate values with custom logic
`all(fn)`	Check if all elements match predicate
`any([fn])`	Check if any element exists or matches
`append(value)`	Append a value to the sequence
`average()`	Compute average (returns `undefined` if non-numeric)
`concat(...iterables)`	Concatenate multiple sequences
`contains(value, [comparer])`	Check for value presence
`count()`	Count elements
`defaultIfEmpty(val)`	Provide default if empty
`distinct([comparer])`	Unique values with optional comparer
`duplicate(n, inplace)`	Repeat sequence `n` times
`elementAt(i)` / `elementAtOrDefault(i, def)`	Get item by index (or fallback)
`empty()`	Return an empty sequence
`except(other, [comparer])`	Exclude items in another iterable
`first([fn])` / `firstOrDefault(def, [fn])`	Get first (matching) element
`forEach(fn)`	Run function for each item
`groupBy(keyFn, elFn, resFn, cmp)`	Group by key with full control
`groupJoin(...)`	Join left with grouped-right by key
`intersect(other, [cmp])`	Common unique elements
`join(...)`	Standard inner join
`last([fn])` / `lastOrDefault(def, [fn])`	Get last (matching) element
`max([cmp])` / `min([cmp])`	Get maximum/minimum value
`orderBy([keyFn], [cmp])`	Sort ascending
`orderByDescending(...)`	Sort descending
`thenBy(...)` / `thenByDescending(...)`	Chain ordering
`prepend(value)`	Add value at start
`range(start, count)`	Generate integer range
`removeNullishes()`	Filter out `null`/`undefined`
`repeat(value, count)`	Repeat value `count` times
`reverse()`	Reverse sequence
`select(fn)`	Transform each element
`selectMany(collFn, resFn)`	Flatten nested sequences
`sequenceEqual(other, [cmp])`	Compare two sequences
`single([fn])` / `singleOrDefault(def, [fn])`	Enforce single (matching) element
`skip(n)` / `skipLast(n)`	Skip `n` items (from start/end)
`skipWhile(fn)`	Skip until predicate fails
`statistics([extended])`	Return statistics object
`sum()`	Sum of all elements
`take(n)` / `takeLast(n)`	Take `n` items (from start/end)
`takeWhile(fn)`	Take while predicate passes
`toArray()`	Convert to array
`toMap(keyFn, valFn)`	Build Map from sequence
`toDictionary(...)`	Alias for `toMap`
`toSet([keyFn])`	Build Set from sequence
`where(fn)`	Filter by predicate
`union(other, [cmp])`	Union of sequences (unique values)
`zip(iter1, iter2, transform)`	Zip two sequences with transform
`Statistics`	Encapsulates count, average, median, mode, etc.

Note: Many methods support optional thisArg to bind context in user-defined functions.

Version Access

Access the library version directly:

import * as myLib from "@moyal/js-linq";

myLib.Version // → e.g., "1.0.4"

License

MIT License - free to use, modify, and distribute.

Author: Ilan Moyal

Website: https://www.moyal.es

GitHub: Ilan Moyal

LinkedIn: Ilan Moyal