webauthn-polyfills

Polyfills for advanced WebAuthn methods not yet supported in evergreen browsers.

A polyfill is a piece of code used to provide modern functionality on older browsers that do not natively support it.

Supported APIs

Just by importing webauthn-polyfills, your WebAuthn implementation will get the following support so you don't have to worry about backward compatibility:

JSON serialization

WebAuthn request and response objects have multiple fields that contain raw binary data in an ArrayBuffer, such as the credential ID, user ID, or challenge. If a website wants to use JSON to exchange this data with its server, the binary data must first be encoded, for example with Base64URL. This adds unnecessary complexity for developers that want to start using passkeys on their websites.

WebAuthn offers APIs to parse PublicKeyCredentialCreationOptions and PublicKeyCredentialRequestOptions WebAuthn request objects directly from JSON, and serialize the PublicKeyCredential response directly into JSON. All ArrayBuffer-valued fields that carry raw binary data are automatically converted from or to their Base64URL-encoded values.

• PublicKeyCredential.parseCreationOptionsFromJSON
• PublicKeyCredential.parseRequestOptionsFromJSON
• PublicKeyCredential.prototype.toJSON

getClientCapabilities()

getClientCapabilities() method allows to determine which WebAuthn features are supported by the user's client. The method returns a list of supported capabilities, allowing developers to tailor authentication experiences and workflows based on the client's specific functionality. Expected results include:

• PublicKeyCredential.getClientCapabilities

This polyfill returns static results based on the user agent information.

Installation

This package can be installed from NPM:

npm install webauthn-polyfills

This package is also available from JSR.io:

npx jsr add @passkeys/webauthn-polyfills
deno add jsr:@passkeys/webauthn-polyfills

Contributing

Requirements:

• Deno v2.0.x

# Install dependencies
$ deno install

# Run tests once
$ deno task test

# Re-run tests on changes
$ deno task test:watch

Publishing

🚨 Increment "version" in deno.json before proceeding! 🚨

NPM

To publish to NPM, run the following command:

$ deno task publish:npm

JSR

The following command will publish to JSR.io:

$ deno task publish:jsr