inthash

Integer Hashing Library based on Knuth’s multiplicative hashing method for Javascript(& Typescript).

Installation

Node.js

npm install inthash

import { Hasher } from "inthash";

//

Deno

import { Hasher } from "https://deno.land/x/inthash/mod.ts";

//

Usage

3 values are required before using inthash.

1. Prime
2. Inverse
3. Xor (Random Number)

Fortunately, we provide the CLI tool also.

npx inthash
# deno run https://deno.land/x/inthash/cli.ts

{
  "bits": 53,
  "prime": "6456111708547433",
  "inverse": "3688000043513561",
  "xor": "969402349590075"
}

Copy the output code and paste it into your project.

There are only two methods. encode and decode.

const hasher = new Hasher({
  bits: 53, // Javascript, Number.MAX_SAFE_INTEGER
  prime: "6456111708547433",
  inverse: "3688000043513561",
  xor: "969402349590075",
});

const encoded = hasher.encode(100); // 6432533451586367
const decoded = hasher.decode(encoded); // 100

Done!

Of course, you can use other types of values as well.

// string
const encoded = hasher.encode("100"); // "6432533451586367"
const decoded = hasher.decode(encoded); // "100"

// bigint
const encoded = hasher.encode(100n); // 6432533451586367n
const decoded = hasher.decode(encoded); // 100n

with MySQL bigint(20)

To handle bigint(20) in mysql, you have to deal with 64bit. In the past inthash library only supported up to 53bit(Number.MAX_SAFE_INTEGER(2^53-1)), the maximum value of JavaScript integer type. From v3.0.0 onwards, 64-bit is also available. :-)

npx inthash -b64
# deno run https://deno.land/x/inthash/cli.ts -b64

{
  "bits": 64,
  "prime": "16131139598801670337",
  "inverse": "14287487925114175297",
  "xor": "8502035541264656686"
}

Refs.

• https://github.com/jenssegers/optimus