@kingjs/linq

Exports all @kingjs/linq.* functionality in one package.

Usage

Join pets to their owners, sorted by last name, then first name, excluding fishes, like this:

var linq = require('@kingjs/linq');
var sequence = require('@kingjs/enumerable.create');
var apply = require('@kingjs/apply');

var people = sequence(
  { firstName: 'Bob', lastName: 'Smith', id: 0 },
  { firstName: 'Alice', lastName: 'Smith', id: 1 },
  { firstName: 'Chris', lastName: 'King', id: 2 },
);

var pets = sequence(
  { name: 'Tiger', type: 'dog', ownerId: 0 },
  { name: 'Spike', type: 'dog', ownerId: 0 },
  { name: 'Fluffy', type: 'cat', ownerId: 1 },
  { name: 'Bubbles', type: 'fish', ownerId: 2 },
);

apply.call(people,
  linq.orderBy, [ function(x) { return x.lastName; } ],
  linq.thenBy, [ function(x) { return x.firstName; } ],
  linq.join, [
    pets, 
    function(x) { return x.id; },
    function(x) { return x.ownerId; },
    function(owner, pet) { return { owner: owner, pet: pet } }
  ],
  linq.where, [ function(x) { return x.pet.type != 'fish'; } ],
  linq.select, [
    function(x) { 
      var owner = x.owner;
      var pet = x.pet;

      return owner.firstName + " " + owner.lastName + 
        ' owns a ' + pet.type + ' named ' + pet.name + '.';
    },
  ],
  linq.toArray, [],
  Array.prototype.join, ['\n']
);

result:

Alice Smith owns a cat named Fluffy. 
Bob Smith owns a dog named Tiger. 
Bob Smith owns a dog named Spike.

API

Search	Aggregate	Set	Generator	Accrete
all	aggregate	distinct	range	append
any	average	except	repeat	concat
contains	count	intersect	empty	prepend
elementAtOrUndef	max	union
firstOrUndef	min
lastOrUndef	sum
singleOrUndef	equal

Sort	Filter	Join	Transform	Container
orderBy	skip	groupBy	select	toArray
orderByDesc	skipWhile	groupJoin	selectMany	toDictionary
thenBy	take	join		toLookup
thenByDesc	takeWhile	zip
	where

Install

With npm installed, run

$ npm install @kingjs/link

Remarks

See @kingjs/apply to understand the benefit of the "odd" apply convention. Basically, it allows for the separation of data from algorithm; Data and algorithm separation cannot be achieved in Javascript using the dot syntax without polluting the data object or prototype with a function.

See Also

• @kingjs/enumerable.define
• @kingjs/make-enumerable
• @kingjs/define-generator

Acknowledgments

Like LINQ.

License

MIT