1 files changed, 28 insertions, 0 deletions
diff --git a/packages/browser/src/helpers/browserSupportsWebAuthnAutofill.ts b/packages/browser/src/helpers/browserSupportsWebAuthnAutofill.ts
new file mode 100644
index 0000000..ffca77d
--- /dev/null
+++ b/packages/browser/src/helpers/browserSupportsWebAuthnAutofill.ts
@@ -0,0 +1,28 @@
+/* eslint-disable @typescript-eslint/ban-ts-comment */
+import { PublicKeyCredentialFuture } from '@simplewebauthn/typescript-types';
+
+/**
+ * Determine if the browser supports conditional UI, so that WebAuthn credentials can
+ * be shown to the user in the browser's typical password autofill popup.
+ */
+export async function browserSupportsWebAuthnAutofill(): Promise<boolean> {
+  // Just for Chrome Canary right now; the PublicKeyCredential logic below is the real API
+  // @ts-ignore
+  if (navigator.credentials.conditionalMediationSupported) {
+    return true;
+  }
+
+  /**
+   * I don't like the `as unknown` here but there's a `declare var PublicKeyCredential` in
+   * TS' DOM lib that's making it difficult for me to just go `as PublicKeyCredentialFuture` as I
+   * want. I think I'm fine with this for now since it's _supposed_ to be temporary, until TS types
+   * have a chance to catch up.
+   */
+  const globalPublicKeyCredential =
+    window.PublicKeyCredential as unknown as PublicKeyCredentialFuture;
+
+  return (
+    globalPublicKeyCredential.isConditionalMediationAvailable !== undefined &&
+    globalPublicKeyCredential.isConditionalMediationAvailable()
+  );
+}