feat: add monad testnet (#3301)

Co-authored-by: Peng Ke <[email protected]>

.changeset/orange-poets-lie.md

@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+Added Monad Testnet.

src/chains/definitions/monadTestnet.ts

@@ -0,0 +1,29 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const monadTestnet = /*#__PURE__*/ defineChain({
+  id: 10_143,
+  name: 'Monad Testnet',
+  nativeCurrency: {
+    name: 'Testnet MON Token',
+    symbol: 'MON',
+    decimals: 18,
+  },
+  rpcUrls: {
+    default: {
+      http: ['https://testnet-rpc.monad.xyz'],
+    },
+  },
+  blockExplorers: {
+    default: {
+      name: 'Monad Testnet explorer',
+      url: 'https://testnet.monadexplorer.com',
+    },
+  },
+  contracts: {
+    multicall3: {
+      address: '0xcA11bde05977b3631167028862bE2a173976CA11',
+      blockCreated: 251449,
+    },
+  },
+  testnet: true,
+})

src/chains/index.ts

@@ -305,6 +305,7 @@ export { mintSepoliaTestnet } from './definitions/mintSepoliaTestnet.js'
 export { mitosisTestnet } from './definitions/mitosisTestnet.js'
 export { mode } from './definitions/mode.js'
 export { modeTestnet } from './definitions/modeTestnet.js'
+export { monadTestnet } from './definitions/monadTestnet.js'
 export { moonbaseAlpha } from './definitions/moonbaseAlpha.js'
 export { moonbeam } from './definitions/moonbeam.js'
 export { moonbeamDev } from './definitions/moonbeamDev.js'