a1rpun/jinq.js

JavaScript Integrated Query for generators and arrays. Inspired by LINQ

jinq.js

JavaScript Integrated Query for generators and arrays. Inspired by LINQ

For vanillajs and nodejs

📄 Wiki

• Installation
• Usage examples
• How jinq deviates from LINQ
• Enumerable methods
  • Static methods

Installation

For now™ use:

$ npm i github:A1rPun/jinq.js

And then import it like:

import { jinq } from 'jinq';

Usage examples

Use jinq.from to construct an Enumerable from an iterator or an array.

function* generator() {
  yield 1;
  yield 2;
  yield 3;
}

const numberText = jinq
  .from(generator())
  .skip(2)
  .take(1)
  .select((n) => `The number: ${n}`)
  .single();

numberText === 'The number: 3'; // true

Use jinq.range to construct a generated sequence of numbers.

const bigRange = jinq.range(0, Number.MAX_SAFE_INTEGER);

bigRange.any(); // true
bigRange.take(2).toList(); // [0, 1]

How jinq deviates from LINQ

• EqualityComparer is not implemented

Enumerable methods

JavaScript has numerous built in methods to do operations on arrays, not so much for generators. This library focuses primarely on generators because of the lazy loading with yields.

Method	Returns value	Description	JS alternative
aggregate()	✅		Array.reduce()
all()	✅		Array.every()
any()	✅		Array.some()
append()			Array.push()
asEnumerable()			yield* Iterator
average()	✅		Array.reduce()
cast()		accepts a type as parameter e.g. String, Number or Boolean	Array.map()
chunk()			-
concat()			Array.concat()
contains()	✅		Array.includes()
count()	✅		Array.length
defaultIfEmpty()			-
distinct()			-
distinctBy()			-
elementAt()	✅	can throw an error	Array.at() ?? throw new Error()
elementAtOrDefault()	✅		Array.at() ?? defaultValue
except()			Array.filter()
exceptBy()			Array.filter()
first()	✅	can throw an error	Array.at(0) ?? throw new Error()
firstOrDefault()	✅		Array.at(0) ?? defaultValue
groupBy()			-
groupJoin()			-
intersect()			-
intersectBy()			-
join()			-
last()	✅	can throw an error	Array.at(-1) ?? throw new Error()
lastOrDefault()	✅		Array.at(-1) ?? defaultValue
longCount()	✅		Array.length
max()	✅		Array.reduce()
maxBy()	✅		Array.reduce()
min()	✅		Array.reduce()
minBy()	✅		Array.reduce()
ofType()			Array.filter()
order()		doesn't return an IOrderedEnumerable	Array.sort()
orderBy()		doesn't return an IOrderedEnumerable	Array.sort()
orderByDescending()		doesn't return an IOrderedEnumerable	Array.sort()
prepend()			Array.unshift()
reverse()			Array.reverse()
select()			Array.map()
selectMany()			Array.flatMap()
sequenceEqual()	✅		Array.all()
single()	✅	can throw an error	-
singleOrDefault()			Array.at(index) ?? defaultValue
skip()			Array.slice()
skipLast()			Array.slice()
skipWhile()			Array.slice()
sum()	✅		Array.reduce()
take()			Array.slice()
takeLast()			Array.slice()
takeWhile()			Array.slice()
toArray()	✅		[...Iterator]
toDictionary()	✅		new Map(Array)
toHashSet()	✅		new Set(Array)
toList()	✅	same as toArray()	[...Iterator]
toLookup()	✅		new Map(Array)
tryGetNonEnumeratedCount()	✅	returns the count if enumerated, otherwise undefined	Array.length
union()			-
unionBy()			-
where()			Array.filter()
zip()			-

Static methods

• jinq.empty()
• jinq.from()
• jinq.range()
• jinq.repeat()