feat: make filterAccountChains optional

src/api.ts

@@ -47,9 +47,31 @@ export const KeyringAccountStruct = object({
   ]),
 
   /**
-   * Account main address.
+   * Account addresses for different chains. Can be used to support Smart
+   * Contract accounts with different addresses on different chains.
+   *
+   * @example
+   * ```ts
+   * address: {
+   *   // Different addresses per chain.
+   *   'eip155:1': ['0x1234...'],
+   *   'eip155:137': ['0x5678...'],
+   * }
+   * ```
+   * @example
+   * ```ts
+   * address: {
+   *   // The address is the same across all 'eip155' chains.
+   *   'eip155': ['0x1234...'],
+   * }
+   * ```
+   * @example
+   * ```ts
+   * // Assumed to be under the 'eip155' namespace.
+   * address: '0x1234...',
+   * ```
    */
-  address: string(),
+  address: union([string(), record(string(), array(string()))]),
 
   /**
    * Account options.
@@ -68,6 +90,26 @@ export const KeyringAccountStruct = object({
  */
 export type KeyringAccount = Infer<typeof KeyringAccountStruct>;
 
+/**
+ * A struct which represents a blockchain account object.
+ */
+export type BlockchainAccount = {
+  /**
+   * Account address.
+   */
+  address: string;
+
+  /**
+   * CAIP-2 chain ID or namespace.
+   */
+  chainId: string;
+
+  /**
+   * Account ID of the parent (keyring) account.
+   */
+  parentAccount: string;
+};
+
 export const KeyringRequestStruct = object({
   /**
    * Keyring request ID (UUIDv4).
@@ -209,12 +251,17 @@ export type Keyring = {
   /**
    * Filter supported chains for a given account.
    *
+   * See {@link KeyringAccount}.
+   *
+   * @deprecated Use the keys of the `address` map of the account object to
+   * indicate the supported chains. This method will be removed in a future
+   * version of the Keyring API.
    * @param id - ID of the account to be checked.
    * @param chains - List of chains (CAIP-2) to be checked.
    * @returns A Promise that resolves to a filtered list of CAIP-2 IDs
    * representing the supported chains.
    */
-  filterAccountChains(id: string, chains: string[]): Promise<string[]>;
+  filterAccountChains?(id: string, chains: string[]): Promise<string[]>;
 
   /**
    * Update an account.

src/rpc-handler.test.ts

@@ -131,6 +131,27 @@ describe('keyringRpcDispatcher', () => {
     expect(result).toBe('FilterSupportedChains result');
   });
 
+  it('fails if the `keyring_filterAccountChains` method is not implemented', async () => {
+    const request: JsonRpcRequest = {
+      jsonrpc: '2.0',
+      id: '7c507ff0-365f-4de0-8cd5-eb83c30ebda4',
+      method: 'keyring_filterAccountChains',
+      params: {
+        id: '4f983fa2-4f53-4c63-a7c2-f9a5ed750041',
+        chains: ['chain1', 'chain2'],
+      },
+    };
+
+    const partialKeyring: Keyring = {
+      ...keyring,
+    };
+    delete partialKeyring.filterAccountChains;
+
+    await expect(handleKeyringRequest(partialKeyring, request)).rejects.toThrow(
+      'Method not supported: keyring_filterAccountChains',
+    );
+  });
+
   it('should call keyring_updateAccount', async () => {
     const request: JsonRpcRequest = {
       jsonrpc: '2.0',

src/rpc-handler.ts

@@ -61,6 +61,9 @@ export async function handleKeyringRequest(
     }
 
     case KeyringRpcMethod.FilterAccountChains: {
+      if (keyring.filterAccountChains === undefined) {
+        throw new MethodNotSupportedError(request.method);
+      }
       assert(request, FilterAccountChainsStruct);
       return keyring.filterAccountChains(
         request.params.id,