PublicKeyCredential.getClientCapabilities - add

files/en-us/web/api/publickeycredential/getclientcapabilities_static/index.md

@@ -0,0 +1,101 @@
+---
+title: "PublicKeyCredential: getClientCapabilities() static method"
+short-title: getClientCapabilities()
+slug: Web/API/PublicKeyCredential/getClientCapabilities_static
+page-type: web-api-static-method
+browser-compat: api.PublicKeyCredential.getClientCapabilities_static
+---
+
+{{APIRef("Web Authentication API")}}{{securecontext_header}}
+
+The **`getClientCapabilities()`** static method of the {{domxref("PublicKeyCredential")}} interface returns a {{jsxref("Promise")}} that resolves with a {{jsxref("Map")}} that can be used to check whether or not particular WebAuthn Client capabilities and [extensions](/en-US/docs/Web/API/Web_Authentication_API/WebAuthn_extensions) are supported.
+
+If the value of a given capability is present in the map, then `true` indicates that the capability is currently supported, and `false` indicates that it is not.
+However if a key is not present for a particular capability, no assumptions can be made about the availability of the associated feature.
+
+For an extension the assumptions are the same, but note that generally if an extension is implemented the value will be `true`.
+Note however that even if the extension is supported by the client a particular authenticator may not support that extension, so RPs must not assume that this is a guarantee that the authenticator processing steps for that extension will be performed.
+If the key is not present for an extension then a Relying Party (RP) can't assume that client processing steps for that extension will be carried out by this client or that the extension will be forwarded to the authenticator.
+
+A WebAuthn Relying Party can evaluate these to offer appropriate workflows and experiences to users.
+
+## Syntax
+
+```js-nolint
+PublicKeyCredential.getClientCapabilities()
+```
+
+### Parameters
+
+None.
+
+### Return value
+
+A {{jsxref("Promise")}} that resolves to a {{jsxref("Map")}} of client capability strings and a boolean indicating whether or not the corresponding capability or extension is supported.
+
+The client capability strings are:
+
+- `conditionalCreate`
+  - : The WebAuthn Client is capable of conditional mediation for registration ceremonies.
+- `conditionalGet`
+  - : The WebAuthn Client is capable of conditional mediation for authentication ceremonies.
+    This capability is equivalent to isConditionalMediationAvailable() resolving to true.
+- `hybridTransport`
+  - : The WebAuthn Client supports usage of the hybrid transport.
+- `passkeyPlatformAuthenticator`
+  - : The WebAuthn Client supports usage of a passkey platform authenticator, locally and/or via hybrid transport.
+- `userVerifyingPlatformAuthenticator`
+  - : The WebAuthn Client supports usage of a user-verifying platform authenticator.
+- `relatedOrigins`
+  - : The WebAuthn Client supports Related Origin Requests.
+- `signalAllAcceptedCredentials`
+  - : The WebAuthn Client supports signalAllAcceptedCredentials().
+- `signalCurrentUserDetails`
+  - : The WebAuthn Client supports signalCurrentUserDetails().
+- `signalUnknownCredential`
+  - : The WebAuthn Client supports signalUnknownCredential().
+
+The [web extension](/en-US/docs/Web/API/Web_Authentication_API/WebAuthn_extensions) strings are formatted by prefixing the [extension identifier](/en-US/docs/Web/API/Web_Authentication_API/WebAuthn_extensions#available_extensions) with the prefix `extension:`.
+For example, the key `extension.appid` can be used to check if the [`appid` extension](/en-US/docs/Web/API/Web_Authentication_API/WebAuthn_extensions#appid) is supported.
+
+### Exceptions
+
+The returned {{jsxref("Promise")}} may be rejected with the following values:
+
+- `NotAllowedError` {{domxref("DOMException")}}
+  - : The Web Authentication API is not allowed in the current browsing context.
+    For example, it might be blocked by a permission policy.
+
+## Examples
+
+<!--
+```js
+PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable()
+  .then((available) => {
+    if (available) {
+      // We can proceed with the creation of a PublicKeyCredential
+      // with this authenticator
+    } else {
+      // Use another kind of authenticator or a classical login/password
+      // workflow
+    }
+  })
+  .catch((err) => {
+    // Something went wrong
+    console.error(err);
+  });
+```
+
+-->
+
+## Specifications
+
+{{Specifications}}
+
+## Browser compatibility
+
+{{Compat}}
+
+<!--
+## See also
+-->

files/en-us/web/api/publickeycredential/index.md

@@ -33,6 +33,8 @@ The **`PublicKeyCredential`** interface provides information about a public key
 
 ## Static methods
 
+- {{domxref("PublicKeyCredential.getClientCapabilities_static", "PublicKeyCredential.getClientCapabilities()")}}
+  - : Returns a {{jsxref("Promise")}} that resolves with a {{jsxref("Map")}} that can be used to check whether or not particular client capabilities are supported.
 - {{domxref("PublicKeyCredential.isConditionalMediationAvailable_static", "PublicKeyCredential.isConditionalMediationAvailable()")}}
   - : Returns a {{jsxref("Promise")}} which resolves to `true` if conditional mediation is available.
 - {{domxref("PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable_static", "PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable()")}}