shelving/util/random.js

Toolkit for using data in JavaScript.

import { requireDefined } from "./undefined.js";
/** Generate a random integer between two numbers. */
export function getRandom(min = Number.MIN_SAFE_INTEGER, max = Number.MAX_SAFE_INTEGER) {
    return Math.round(Math.random() * (max - min) + min);
}
/** Get a random number that is anything except an existing number. */
export function getRandomExcept(existing, min, max) {
    let num;
    do
        num = getRandom(min, max);
    while (num === existing);
    return num;
}
/**
 * Make a random key, e.g. `xs23r34hhsdx` or `e4m29klrugef`
 * - Not designed to be cryptographically random!
 * - Will probably clash — if you're making a random ID, check for existence of the record before saving.
 * - Designed to be semi-readable, doesn't use capital letters or `i` or `o` or `l` or `u`
 */
export function getRandomKey(length = 12) {
    return Array.from({ length }, getRandomKeyCharacter).join("");
}
const KEY_CHARS = "0123456789abcdefghjkmnpqrstvwxyz";
function getRandomKeyCharacter() {
    return getRandomCharacter(KEY_CHARS);
}
/** Get a random character from a string. */
export function getRandomCharacter(str) {
    return str[getRandom(0, str.length - 1)];
}
/** Get a random item from an array or random character from a string string. */
export function getRandomItem(arr) {
    return requireDefined(arr[getRandom(0, arr.length - 1)]);
}