feat: Add example code for interacting with a contract

packages/thirdweb/README.md

@@ -19,6 +19,65 @@ npm install thirdweb@alpha
 
 ### Backend (Node, Bun, Deno, etc)
 
+#### With Extensions
+
+```ts
+import { createClient } from "thirdweb";
+import { privateKeyWallet } from "thirdweb/wallets/private-key";
+import { balanceOf, mintTo } from "thirdweb/extensions/erc20";
+
+// Step 1: create a client
+const client = createClient({
+  // create a secret key at https://thirdweb.com/dashboard
+  secretKey: process.env.SECRET_KEY as string,
+});
+
+// Step 2: define a contract to interact with
+const contract = client.contract({
+  // the contract address
+  address: "0xBCfaB342b73E08858Ce927b1a3e3903Ddd203980",
+  // the chainId of the chain the contract is deployed on
+  chainId: 5,
+});
+
+// Step 3: read contract state
+const balance = await balanceOf(contract, {
+  address: "0x0890C23024089675D072E984f28A93bb391a35Ab",
+});
+
+console.log("beginning balance", balance);
+
+// Step 4: initialize a wallet
+const wallet = privateKeyWallet(client);
+
+await wallet.connect({ pkey: process.env.PRIVATE_KEY as string });
+
+// Step 5: create a transaction
+const tx = mintTo(contract, {
+  to: "0x0890C23024089675D072E984f28A93bb391a35Ab",
+  amount: 100,
+});
+
+// Step 6: execute the transaction with the wallet
+const receipt = await wallet.sendTransaction(tx);
+
+console.log("tx hash", receipt.transactionHash);
+
+// Step 7: wait for the receipt to be mined
+const txReceipt = await receipt.wait();
+
+console.log(txReceipt);
+
+// Step 8: read contract state
+const newBalance = await balanceOf(contract, {
+  address: "0x0890C23024089675D072E984f28A93bb391a35Ab",
+});
+
+console.log("ending balance", newBalance);
+```
+
+#### Without Extensions
+
 ```ts
 import { createClient } from "thirdweb";
 import { privateKeyWallet } from "thirdweb/wallets/private-key";