Update Ethereum provider example

Author: Mrtenz

packages/examples/packages/ethereum-provider/snap.manifest.json

@@ -7,7 +7,7 @@
     "url": "https://github.com/MetaMask/snaps.git"
   },
   "source": {
-    "shasum": "zLYiM3hZxvbSmXsvp2rA8G5wYvR8EjWBkUxiICBQRsE=",
+    "shasum": "TVujszFS0k34sSwk9X4zz7uyecPsZM80xhtDpN1xdUg=",
     "location": {
       "npm": {
         "filePath": "dist/bundle.js",

packages/examples/packages/ethereum-provider/src/index.ts

@@ -5,7 +5,19 @@ import {
 import type { Hex } from '@metamask/utils';
 import { assert, stringToBytes, bytesToHex } from '@metamask/utils';
 
-import type { PersonalSignParams } from './types';
+import type { BaseParams, PersonalSignParams } from './types';
+
+/**
+ * Set the active Ethereum chain for the Snap.
+ *
+ * @param chainId - The chain ID to switch to.
+ */
+async function switchChain(chainId: Hex) {
+  await ethereum.request({
+    method: 'wallet_switchEthereumChain',
+    params: [{ chainId }],
+  });
+}
 
 /**
  * Get the current gas price using the `ethereum` global. This is essentially
@@ -106,6 +118,9 @@ async function personalSign(message: string, from: string) {
  * @see https://docs.metamask.io/snaps/reference/rpc-api/#wallet_invokesnap
  */
 export const onRpcRequest: OnRpcRequestHandler = async ({ request }) => {
+  const { chainId = '0x1' } = request.params as BaseParams;
+  await switchChain(chainId);
+
   switch (request.method) {
     case 'getGasPrice':
       return await getGasPrice();

packages/examples/packages/ethereum-provider/src/types.ts

@@ -1,3 +1,9 @@
-export type PersonalSignParams = {
+import type { Hex } from '@metamask/utils';
+
+export type BaseParams = {
+  chainId?: Hex;
+};
+
+export type PersonalSignParams = BaseParams & {
   message: string;
 };