Fallback webcrypto to global

[sergiocarneiro]

Fallback to globalThis.crypto when node:crypto exists but crypto.webcrypto does not.

It also adds the ability to throw MissingWebCrypto when webcrypto is missing.

This change makes the getWebCrypto function more robust and able to work in more runtime setups (e.g. Cloudflare Workers with node_compat enabled).

[MasterKale]

This change makes the getWebCrypto function more robust and able to work in more runtime setups (e.g. Cloudflare Workers with node_compat enabled).

Hello @sergiocarneiro, I'm wondering what the exact problem is you were having with the current way of picking which WebCrypto to use. Are you trying to make globalThis.crypto the default the library tries to reach for Node's because it somehow causes issues with non-Node runtimes?

[sergiocarneiro]

I'm wondering what the exact problem is you were having with the current way of picking which WebCrypto to use.

Hello @MasterKale. In my Cloudflare Worker, I have Node polyfills enabled. I'm not sure if it's a bug from their platform or not, but I know that what ends up happening is an environment that:

• has globalThis.crypto
• allows imports of node:crypto
• crypto.webcrypto is undefined

So without this change I submitted, using functions such as getRegistrationOptions throws the error "Cannot read properties of undefined (reading 'getRandomValues')" — the method is available through globalThis.crypto.

---

Are you trying to make globalThis.crypto the default?

Yes, and only override it if crypto.webcrypto is defined, not if node:crypto can be imported.

[CameronWhiteside]

+1 to this issue--would love to use this in a Cloudflare worker, but without @sergiocarneiro's updates, I'm also fully blocked with the same "Cannot read properties of undefined (reading 'getRandomValues')" issue.

[MasterKale]

@sergiocarneiro Thank you for the contribution. I took a stab at solving this problem with #468, and I also managed to add test coverage around getWebCrypto() that should ensure support for runtimes like your CF worker w/Node compat. In particular this test should capture the nuance of the runtime issue you've been experiencing:

https://github.com/MasterKale/SimpleWebAuthn/pull/468/files#diff-6ac413926c71b2fbaa8af5cffcb57c492adf245dc0d0ec40ec6ba179c537debcR88-R119

Tests just passed over there so I'm going to merge and cut a release with this fix tomorrow.