atomic-fns/dist/random/index.js

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/**
 * This module implements pseudo-random generators for various distributions.
 *
 * @module random
 */
import { isObject } from '../globals/index.js';
/**
 * Returns a random float between a [min, max) value (max exclusive).
 * @param {number} min
 * @param {number} max
 * @returns {number}
 */
export function random(min = 0, max = 1) {
    return Math.random() * (max - min) + min;
}
/**
 * Returns a random integer between a [min, max] value (inclusive).
 * @param {number} min
 * @param {number} max
 * @returns {number}
 */
export function randomInt(min = 0, max = 1) {
    return Math.round(random(min, max));
}
/**
 * Returns the item at some random index in a sequence.
 * @returns {T}
 * @template T
 */
export function choice(arr) {
    if (!arr?.length)
        return;
    return arr[randomInt(0, arr.length - 1)];
}
/**
 * Returns a random sample of size k from a list of items.
 * @param {Array} arr
 * @param {number} size
 * @returns A new array with `size` random elements from `arr`.
 * @template T
 */
export function sample(arr, size) {
    if (!arr?.length || arr.length < size)
        return [];
    return shuffle(arr.slice()).slice(-size);
}
/**
 * Shuffles a collection elements in-place. Uses the Fisher-Yates algorithm for uniform shuffling. If collection is an Object it returns shuffled `Object.values()`.
 *
 * @param {Array} arr
 * @param {number} size
 * @returns The shuffled array.
 * @template T
 */
export function shuffle(arr, size) {
    if (!arr?.length)
        return arr;
    if (isObject(arr))
        arr = Object.values(arr);
    if (size == null)
        size = arr.length - 1;
    for (let i = 0; i <= size; i++) {
        const j = randomInt(i, size);
        const temp = arr[j];
        arr[j] = arr[i];
        arr[i] = temp;
    }
    return arr;
}