Perform a non-destructive weighted shuffle on a collection. Based on the algorithms described in Weighted Random Sampling (2005; Efraimidis, Spirakis).
$ npm i weighted-shuffleTypeScript declarations are included.
The package exports one function, shuffle, which takes two arguments. The first argument is the input collection, which is an object on the form {value: weight, ...}, or an array of tuples on the form [[value, weight], ...]. The second argument is optional and either 'asc' or 'desc'. See below for examples.
The weight must always be a number. If it's not a number, the behavior of this library is undefined.
Since object property keys must be strings in JavaScipt, the same applies to this package.
In the array-tuple form, the value can be anything. The output is always an array of tuples on the form [value, weight] where weight is a value between 0 and 1 based on the input weight.
$ node
> const { shuffle } = require('weighted-shuffle')
undefined
> shuffle({ a: 1, b: 2, c: 3, d: 4 })
[ [ 'a', 0.3332369734469953 ],
[ 'd', 0.4435102443860357 ],
[ 'b', 0.634610481335515 ],
[ 'c', 0.6893187374490146 ] ]
> shuffle([['a', 1], ['b', 2], ['c', 3], ['d', 4]])
[ [ 'a', 0.17752200849829158 ],
[ 'd', 0.4915930588445954 ],
[ 'b', 0.5257541251818763 ],
[ 'c', 0.8857869178489653 ] ]
> shuffle({ a: 1, b: 2, c: 3, d: 4 }, 'desc')
[ [ 'b', 0.8705423064592988 ],
[ 'c', 0.729363245199407 ],
[ 'd', 0.6693826180657991 ],
[ 'a', 0.25133205081259735 ] ]- Make a PR!