fix: _handleChainChanged in MetaMaskInpageProvider to handle networkVersion

src/BaseProvider.rpc.test.ts

@@ -309,4 +309,24 @@ describe('BaseProvider: RPC', () => {
       });
     });
   });
+  describe('provider events', () => {
+    // eslint-disable-next-line jest/no-test-callback
+    it('calls chainChanged when it chainId changes ', (done) => {
+      const mockStream = new MockDuplexStream();
+      const p = new BaseProvider(mockStream);
+      (p as any)._state.initialized = true;
+      p.on('chainChanged', (changed) => {
+        expect(changed).toBeDefined();
+        done();
+      });
+      mockStream.push({
+        name: 'metamask-provider',
+        data: {
+          jsonrpc: '2.0',
+          method: 'metamask_chainChanged',
+          params: { chainId: '0x1' },
+        },
+      });
+    });
+  });
 });

src/BaseProvider.ts

@@ -420,32 +420,21 @@ export default class BaseProvider extends SafeEventEmitter {
    */
   protected _handleChainChanged({
     chainId,
-    networkVersion,
   }: { chainId?: string; networkVersion?: string } = {}) {
-    if (
-      !chainId ||
-      typeof chainId !== 'string' ||
-      !chainId.startsWith('0x') ||
-      !networkVersion ||
-      typeof networkVersion !== 'string'
-    ) {
+    if (!chainId || typeof chainId !== 'string' || !chainId.startsWith('0x')) {
       this._log.error(
         'MetaMask: Received invalid network parameters. Please report this bug.',
-        { chainId, networkVersion },
+        { chainId },
       );
       return;
     }
 
-    if (networkVersion === 'loading') {
-      this._handleDisconnect(true);
-    } else {
-      this._handleConnect(chainId);
+    this._handleConnect(chainId);
 
-      if (chainId !== this.chainId) {
-        this.chainId = chainId;
-        if (this._state.initialized) {
-          this.emit('chainChanged', this.chainId);
-        }
+    if (chainId !== this.chainId) {
+      this.chainId = chainId;
+      if (this._state.initialized) {
+        this.emit('chainChanged', this.chainId);
       }
     }
   }

src/MetaMaskInpageProvider.rpc.test.ts

@@ -636,4 +636,42 @@ describe('MetaMaskInpageProvider: RPC', () => {
       );
     });
   });
+  describe('provider events', () => {
+    // eslint-disable-next-line jest/no-test-callback
+    it('calls chainChanged when it chainId changes ', (done) => {
+      const mockStream = new MockDuplexStream();
+      const p = new MetaMaskInpageProvider(mockStream);
+      (p as any)._state.initialized = true;
+      p.on('chainChanged', (changed) => {
+        expect(changed).toBe('0x1');
+        done();
+      });
+      mockStream.push({
+        name: 'metamask-provider',
+        data: {
+          jsonrpc: '2.0',
+          method: 'metamask_chainChanged',
+          params: { chainId: '0x1', networkVersion: '0x1' },
+        },
+      });
+    });
+    // eslint-disable-next-line jest/no-test-callback
+    it('calls networkChanged when it networkVersion changes ', (done) => {
+      const mockStream = new MockDuplexStream();
+      const p = new MetaMaskInpageProvider(mockStream);
+      (p as any)._state.initialized = true;
+      p.on('networkChanged', (changed) => {
+        expect(changed).toBe('0x1');
+        done();
+      });
+      mockStream.push({
+        name: 'metamask-provider',
+        data: {
+          jsonrpc: '2.0',
+          method: 'metamask_chainChanged',
+          params: { chainId: '0x1', networkVersion: '0x1' },
+        },
+      });
+    });
+  });
 });

src/MetaMaskInpageProvider.ts

@@ -395,4 +395,54 @@ export default class MetaMaskInpageProvider extends BaseProvider {
       },
     );
   }
+
+  /**
+   * Upon receipt of a new chainId and networkVersion, emits corresponding
+   * events and sets relevant public state.
+   * Does nothing if neither the chainId nor the networkVersion are different
+   * from existing values.
+   *
+   * @emits MetamaskInpageProvider#chainChanged
+   * @param networkInfo - An object with network info.
+   * @param networkInfo.chainId - The latest chain ID.
+   * @param networkInfo.networkVersion - The latest network ID.
+   */
+  protected _handleChainChanged({
+    chainId,
+    networkVersion,
+  }: { chainId?: string; networkVersion?: string } = {}) {
+    if (
+      !chainId ||
+      typeof chainId !== 'string' ||
+      !chainId.startsWith('0x') ||
+      !networkVersion ||
+      typeof networkVersion !== 'string'
+    ) {
+      this._log.error(
+        'MetaMask: Received invalid network parameters. Please report this bug.',
+        { chainId, networkVersion },
+      );
+      return;
+    }
+
+    if (networkVersion === 'loading') {
+      this._handleDisconnect(true);
+    } else {
+      this._handleConnect(chainId);
+
+      if (chainId !== this.chainId) {
+        this.chainId = chainId;
+        if (this._state.initialized) {
+          this.emit('chainChanged', this.chainId);
+        }
+      }
+
+      if (networkVersion !== this.networkVersion) {
+        this.networkVersion = networkVersion;
+        if (this._state.initialized) {
+          this.emit('networkChanged', this.networkVersion);
+        }
+      }
+    }
+  }
 }