Web worker support

[perry-mitchell]

This PR adds support for detecting crypto within a Web Worker, where window is not defined but self (and therefore self.crypto) is.

Fixes #83

[codecov-io]

Codecov Report

Merging #82 (63d6d45) into master (a583120) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #82   +/-   ##
=======================================
  Coverage   93.08%   93.08%           
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  Files           2        2           
  Lines         246      246           
  Branches       31       31           
=======================================
  Hits          229      229           
  Misses         17       17           

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[lucaslago]

Hi, any reason this hasn't been merged?

[DavidJFelix]

Hey, if anyone else finds this issue like I did and is using cloudflare workers, here's what worked for me:

import {monotonicFactory} from 'ulid'
// or import {factory} from 'ulid'

const prng = () => {
  const buffer = new Uint8Array(1)
  crypto.getRandomValues(buffer)
  return buffer[0] / 0xff
}
export const ulid = monotonicFactory(prng) // or factory(prng)

This will bypass the code that checks for browser crypto and allow you to set your own. The PRNG function is the same as used internally with a different global reference.

I think this package may be abandoned, I'm working on potentially forking it.