Loq NPM | npm.io

Note: this package is deprecated and has been replaced by https://github.com/biggyspender/blinq/

loq.js

A linq inspired library for javascript

Why?

With the advent of javascript iterators and generators, its possible to pipe sequences through a bunch of transformations without materializing collections (arrays) for the intermediate steps. This library attempts to recreate the dotnet linq-to-objects api to provide a number of standard operations on iterable sequences.

How?

Just wrap your iterable with a call to loq(myIterable), and start transforming your data:

const someNumbers = [1, 2, 3, 4];
const squares = loq(someNumbers).select(n => n * n);
for(let v of squares){
    console.log(v);
}

...or if you'd like an array of your results, you can materialize a loq query with the .toArray() method:

const someNumbers = loq.range(1, 4);
const squaresBelowTen = someNumbers.select(n => n * n).where(n => n < 10);
const arr = squaresBelowTen.toArray();
console.log(arr);

More examples:

Let's make a collection of cars:

const cars = [{
    manufacturer:"Ford",
    model:"Escort"
  },{
    manufacturer:"Ford",
    model:"Cortina"
  },{
    manufacturer:"Renault",
    model:"Clio"
  },{
    manufacturer:"Vauxhall",
    model:"Corsa"
  },{
    manufacturer:"Ford",
    model:"Fiesta"
  },{
    manufacturer:"Fiat",
    model:"500"
  }
];

...and sort them by manufacturer, and then by model:

const orderedCars = loq(cars).orderBy(c => c.manufacturer).thenBy(c => c.model);
console.log(orderedCars.toArray());

Or we could count the number of cars for each manufacturer:

const carsPerManufacturer = loq(cars)
  .groupBy(c => c.manufacturer)
  .select(g => ({
    manufacturer:g.key, 
    count:g.count()
  }))
  .orderBy(c => c.manufacturer);
for(var c of carsPerManufacturer){
  console.log(`${c.manufacturer} : ${c.count}`);
}