Liking cljdoc? Tell your friends :D

nano-id

A tiny, secure, URL-friendly unique string ID generator for Clojure and ClojureScript.

Secure. It uses cryptographically strong random APIs.
Fast. It's ~35% faster than jnanoid, and almost as fast as UUID.
Compact. It uses a larger alphabet than UUID (A-Za-z0-9_-). So ID size was reduced from 36 to 21 symbols.
URL-Firendly. It uses only URL-friendly characters. Perfect for unique identifiers in web applications.

clj -Sdeps '{:deps {nano-id {:mvn/version "1.0.0"}}}'

(require '[nano-id.core :refer [nano-id]])
(nano-id) ;; => "trxwfoC8mqB3Q8Wrdq4OQ"

Benchmark

$ lein bench

## Actually, you will get more detailed info, this is summary.

UUID               1.60µs
nano-id            1.69µs
jnanoid            2.77µs
nano-id (custom)   2.25µs
jnanoid (custom)   2.57µs

Configuration:

MacBook Air (mid 2013), 1.3 GHz Intel Core i5, 8GB RAM;
Java(TM) SE Runtime Environment (build 1.8.0_251-b08);
Clojure 1.10.1.

Usage

Default ID generator

The default implementation uses 64-character alphabet and generates 21-character IDs.

user=> (require '[nano-id.core :refer [nano-id]])
nil

user=> (nano-id)
"NOBHihn110UuXbF2JiKxT"

If you want to reduce the ID size (and increase collision probability), you can pass the size as an argument.

user=> (nano-id 10)
"N2g6IlJP0l"

Don’t forget to check the safety of your ID size via collision probability calculator.

If for whatever reason the default implementation doesn't fit your project, you can build your own ID generator just passing your alphabet and ID size in custom function. It will give you back a new generator:

user=> (require '[nano-id.core :refer [custom]])
nil

user=> (def my-nano-id (custom ".-" 6))
#'user/my-nano-id

user=> (my-nano-id)
"-.---."

Also you can provide your random bytes generator. In the example below we use this feature to encode the current time:

(let [alphabet "-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz"
      time-gen (fn [n]
                 (->> (quot (System/currentTimeMillis) 1000)
                      (iterate #(unsigned-bit-shift-right % 6))
                      (take n)
                      reverse
                      byte-array))
      time-id  (custom alphabet 6 time-gen)]
  (time-id))
"0TfMui"

This encodes current time using a lexicographical alphabet.