@naturalcycles/js-lib/dist/string/hash.util.js

Standard library for universal (browser + Node.js) javascript

const BASE62 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
// const BASE64 = BASE62 + '+/'
const BASE64URL = BASE62 + '-_';
/**
 * Returns hashCode as hex (radix 16).
 *
 * All hash functions here are optimized for:
 *
 * 1. Performance
 * 2. For non-cryptographic use (where accidental collision is not the end-of-the-world)
 * 3. Compact size (32 bits max, versus 128 in md5; presented in smaller number of string json-safe characters)
 *
 * Basically, these functions are as simple as they can be, but still "random enough" for
 * normal non-cryptographic use cases.
 *
 * To be run on the ClientSide, as in Node there are plenty of other hash options in `node:crypto`.
 *
 * Perf: it runs ~10 times faster than CryptoJS md5, and ~3 times smaller String hash size (for
 * hashCode64).
 */
export function hashCode16(s) {
    return hashCode(s).toString(16);
}
/**
 * Returns hashCode as "radix 36", using "Base36 alphabet".
 * 36 is used, because it's the maximum "radix" that Number.toString() can take.
 *
 * See the hashCode16 for full description.
 */
export function hashCode36(s) {
    return hashCode(s).toString(36);
}
/**
 * Returns hashCode as "radix 64", using Base64url alphabet.
 * See the hashCode16 for full description.
 */
export function hashCode64(s) {
    return numberToBase(hashCode(s), BASE64URL);
}
/**
 * Generates a stable integer hashCode for a given String.
 * Matches Java implementation (they say), except it ensures a positive Integer
 * by adding 2147483647 + 1 to the end result.
 * Source: https://stackoverflow.com/a/33647870/4919972
 */
export function hashCode(s) {
    let hash = 0;
    let i = 0;
    const len = s.length;
    while (i < len) {
        // eslint-disable-next-line no-bitwise, unicorn/prefer-math-trunc, unicorn/prefer-code-point
        hash = ((hash << 5) - hash + s.charCodeAt(i++)) << 0;
    }
    return hash + 2147483647 + 1;
}
/**
 * Source: https://gist.github.com/alkaruno/b84162bae5115f4ca99b
 */
function numberToBase(n, alphabet) {
    const alen = alphabet.length;
    let result = '';
    do {
        result = alphabet.charAt(n % alen) + result;
        n = Math.floor(n / alen) - 1;
    } while (n > -1);
    return result;
}