Combinations

Note

Note that this is fork of jgallen23 combinations repository (https://github.com/jgallen23/combinations) without any changes. But since the author did not publish for 3 years (and did not include the last commit), I think it's better to publish myself.

Installation

npm install combinations

Usage

combinations(array[, min_output_array_size])

• takes in an array, and outputs an array of arrays, containing all possible combinations of values in the original array.
• combinations are of all sizes: all combinations of one element, and all combinations of 2 elements, and so on
• minimum number of elements in a combination can be specified (min_output_array_size)
• maximum number of elements in a combination can be also specified
• if maximum combination value is bigger than array elements it will be overridden to the array length

Example

var combinations = require('combinations');
var myArray = ['red', 'orange', 'yellow', 'green'];

combinations(myArray);

//Output:
//  [ [ 'red' ],                      [ 'orange' ],
//    [ 'yellow' ],                   [ 'green' ],
//    [ 'red', 'orange' ],            [ 'red', 'yellow' ],
//    [ 'red', 'green' ],             [ 'orange', 'yellow' ],
//    [ 'orange', 'green' ],          [ 'yellow', 'green' ],
//    [ 'red', 'orange', 'yellow' ],  [ 'red', 'orange', 'green' ],
//    [ 'red', 'yellow', 'green' ],   [ 'orange', 'yellow', 'green' ],
//    [ 'red', 'orange', 'yellow', 'green' ] ]

Example with a minimum array size

combinations(myArray, 2);

//Output:
//  [ [ 'red', 'orange' ],            [ 'red', 'yellow' ],
//    [ 'red', 'green' ],             [ 'orange', 'yellow' ],
//    [ 'orange', 'green' ],          [ 'yellow', 'green' ],
//    [ 'red', 'orange', 'yellow' ],  [ 'red', 'orange', 'green' ],
//    [ 'red', 'yellow', 'green' ],   [ 'orange', 'yellow', 'green' ],
//    [ 'red', 'orange', 'yellow', 'green' ] ]

Example with a minimum and maximum array size

combinations(myArray, 2, 3);

//Output:
//  [ [ 'red', 'orange' ],            [ 'red', 'yellow' ],
//    [ 'red', 'green' ],             [ 'orange', 'yellow' ],
//    [ 'orange', 'green' ],          [ 'yellow', 'green' ],
//    [ 'red', 'orange', 'yellow' ],  [ 'red', 'orange', 'green' ],
//    [ 'red', 'yellow', 'green' ],   [ 'orange', 'yellow', 'green' ] ]