powerset-gen

A generator function that produces all subsets of the given set in input.

Install

npm install powerset-gen

Usage

Both ES6 Module and CommonJS distributions are provided by this package.

ES6 Module

import generator from "poweset-get"

ES5 / CommonJS

var generator = require("powerset-gen");

API

The module exports the following function.

generator(set, [mapper]) ⇒ Generator

| Param | Type | Default | Description | | --- | --- | --- | --- | | set | Array | | The given set in input | | mapper | Function | (value, index) => value | (optional) Function that maps the yielded value, taking two arguments: - value The current subset being generated - index The index of the current subset being generated |

Examples

for..of

for (const subset of generator(["a", "b", "c"])) {
  console.log(subset)
}

Output

[]
["a"]
["b"]
["a", "b"]
["c"]
["a", "c"]
["b", "c"]
["a", "b", "c"]

Generate an Array

[...generator(["a", "b"])]
// or
Array.from(generator(["a", "b"]))

Generate a Set

new Set(generator(["a", "b"]))

Spreading in function call

console.log(...generator(["a", "b"]))

Indexes

for (const [index, subset] of generator(["a", "b", "c"], (value, i) => [i, value])) {
  console.log(index, subset)
}

Output

0 []
1 ["a"]
2 ["b"]
3 ["a", "b"]
4 ["c"]
5 ["a", "c"]
6 ["b", "c"]
7 ["a", "b", "c"]

Binary mask

for (const [mask, subset] of generator(["a", "b", "c"], (value, index) => [index.toString(2), value])) {
  console.log(mask, subset)
}

Output

0 []
1 ["a"]
10 ["b"]
11 ["a", "b"]
100 ["c"]
101 ["a", "c"]
110 ["b", "c"]
111 ["a", "b", "c"]