aguid

A Globally Unique IDentifier (GUID) generator in JS.

Why?

There are already great node module(s) for generating random UUIDs: https://www.npmjs.com/search?q=uuid

What we need is a way to return the same UUID/GUID for a given input string; i.e. Deterministic !

Use Case

The use-case is very specific: generate a key for a record in a database.

Imagine you want to store a person's personal details in a record but don't want use a username or email as the key for the record. We solved this by creating a UUID (string) from the username or email address and using that instead. (see usage below)

Usage

### Install

npm install aguid --save

Generate a Deterministic GUID given an input

var aguid = require('aguid');
var guid  = aguid("[email protected]"); // d828ed52-32ed-4908-86df-df934d3c315d (ALWAYS)
// use the guid as the key for our record in Redis, ElasticSearch, Postgres, etc.

Note: even though the GUID we are returning for a given input is deterministic, it's still globally unique because we are using SHA256 hash for the characters. and in our specific use-case we are hashing an email address (which is its' self unique be definition!)

Generate a Random GUID when invoked without argument

var aguid = require('aguid');
var guid  = aguid(); // 525be54a-1101-46bf-97d7-2e9c89dd1b16 (*Random*)
// use for what ever you need a *random* guid

Research

Background

• Wikipedia UUID (gentler intro): http://en.wikipedia.org/wiki/Universally_unique_identifier
• Universally Unique IDentifier (UUID) Specification: http://tools.ietf.org/html/rfc4122
• V.4 Random UUID: http://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_.28random.29

Implementation

• Hex to Base64 and back: http://stackoverflow.com/questions/23190056/hex-to-base64-converter-for-javascript
• Snowflake approach: http://blog.tompawlak.org/generate-unique-identifier-nodejs-javascript
• GUIDs using Math.random() https://gist.github.com/jed/982883

Dependency

Instead of trying to re-invent this, I invested the time to read, download and play with the source-code for node-uuid (the most popular & performant module for creating GUIDs): https://github.com/broofa/node-uuid See: #3