fast-unique-numbers

A module to create a set of unique numbers as fast as possible.

This module is meant to create unique numbers within a given Map or Set. To achieve that as fast as possible the resulting set of numbers will only contain integers. For as long as possible only small integers will be used. This is a special integer representation that V8 uses to store integers more efficiently.

To verify the expected perfomance benefit an expectation test is used to make sure small integers do actually perform better. A complementary test is used to make sure the perfomance gain achieved in Chromium based browsers and Node.js is not negated by causing unexpected behavior when running in Firefox.

Usage

This module is available on npm and can be installed by running the following command:

npm install fast-unique-numbers

This module exports two functions.

addUniqueNumber()

This function takes a Set of numbers as argument and appends a new unique number to it. It also returns that number.

import { addUniqueNumber } from 'fast-unique-numbers';

const set = new Set([1, 4, 8]);
const uniqueNumber = addUniqueNumber(set);

console.log(uniqueNumber); // 3
console.log(set); // Set(4) { 1, 4, 8, 3 }

generateUniqueNumber()

This function can be used to generate a unique number which is not yet present in the given Set or is no key in the given Map. The resulting number gets not appended. It only gets returned.

import { generateUniqueNumber } from 'fast-unique-numbers';

const map = new Map([
    [1, 'something'],
    [4, 'something else']
]);

const uniqueNumber = generateUniqueNumber(map);

console.log(uniqueNumber); // 2