Ember-cartesian-product

This addon provides a computed property macro that calculates the cartesian product of N arrays.

Installation

ember install ember-cartesian-product

Note: This addon requires ember.js >= 2.0

Usage

The cartesian macro works by accepting a key to another property on the object whose value is an array of N arrays. The computed property's value will be equal to an array of N-tuple arrays, consisting of every distinct combination of one element from each the source arrays. For example, say you have an object with two arrays called animals and colors, and you want to calculate the cartesian product of those arrays.

import Ember from 'ember';
import cartesian from 'ember-cartesian-product';

...

let MyObject = Ember.Object.extend({
  cartesianProduct: cartesian('myArrays')
});

let subject = MyObject.create({
  animals: ['cat', 'dog'],
  colors: ['orange', 'blue'],
  myArrays: Ember.computed.collect('animals', 'colors')
});

// Initial value
subject.get('cartesianProduct');
  /*
   * [
   *   ['cat', 'orange'], ['cat', 'blue'],
   *   ['dog', 'orange'], ['dog', 'blue']
   * ]
   */

// Swapping out one of the arrays
let newColors = Ember.A(['black', 'teal']);
subject.set('colors', newColors);
subject.get('cartesianProduct');
  /*
   * [
   *   ['cat', 'black'], ['cat', 'teal'],
   *   ['dog', 'black'], ['dog', 'teal']
   * ]
   */

// Adding an element to one of the arrays
newColors.pushObject('green');
subject.get('cartesianProduct');
  /*
   * [
   *   ['cat', 'black'], ['cat', 'teal'], ['cat', 'green'],
   *   ['dog', 'black'], ['dog', 'teal'], ['dog', 'green']
   * ]
   */

You can also dynamically change which arrays are being used to calculate the product:

let MyObject = Ember.Object.extend({
  cartesianProduct: cartesian('myArrays')
});

let animals = ['cat', 'dog'];
let colors = ['black', 'teal'];
let myArrays = Ember.A([animals, colors]);
let subject = MyObject.create({
  myArrays: myArrays
});

// Initial value
subject.get('cartesianProduct');
  /*
   * [
   *   ['cat', 'black'], ['cat', 'teal'],
   *   ['dog', 'black'], ['dog', 'teal']
   * ]
   */

// Add a third source array
myArrays.pushObject(['square', 'circle', 'triangle']);
subject.get('cartesianProduct');
  /*
   * [
   *   ['cat', 'black', 'square'], ['cat', 'black', 'circle'], ['cat', 'black', 'triangle']
   *   ['cat', 'teal', 'square'],  ['cat', 'teal', 'circle'],  ['cat', 'teal', 'triangle']
   *   ['dog', 'black', 'square'], ['dog', 'black', 'circle'], ['dog', 'black', 'triangle']
   *   ['dog', 'teal', 'square'],  ['dog', 'teal', 'circle'],  ['dog', 'teal', 'triangle']
   * ]
   */

For more information on using ember-cli, visit http://www.ember-cli.com/.