Fetch native currency from chain API when required

Author: jnsdls

.changeset/forty-donuts-happen.md

@@ -0,0 +1,5 @@
+---
+"thirdweb": patch
+---
+
+fetch native currency from chain API if required

packages/thirdweb/src/extensions/erc20/read/getCurrencyMetadata.ts

@@ -1,9 +1,17 @@
+import z from "zod";
+import { getChainMetadata } from "../../../chains/utils.js";
 import { isNativeTokenAddress } from "../../../constants/addresses.js";
 import type { BaseTransactionOptions } from "../../../transaction/types.js";
 import { name } from "../../common/read/name.js";
 import { symbol } from "../../common/read/symbol.js";
 import { decimals } from "../__generated__/IERC20/read/decimals.js";
 
+const NATIVE_CURRENCY_SCHEMA = z.object({
+  name: z.string().default("Ether"),
+  symbol: z.string().default("ETH"),
+  decimals: z.number().default(18),
+});
+
 /**
  * @extension ERC20
  */
@@ -30,13 +38,18 @@ export async function getCurrencyMetadata(
 ): Promise<GetCurrencyMetadataResult> {
   // if the contract is the native token, return the native currency metadata
   if (isNativeTokenAddress(options.contract.address)) {
-    return {
-      decimals: 18,
-      name: "Ether",
-      symbol: "ETH",
-      // overwrite with native currency of the chain if available
-      ...options.contract.chain.nativeCurrency,
-    };
+    // if the chain definition does not have a native currency, attempt to fetch it from the API
+    if (!options.contract.chain.nativeCurrency) {
+      try {
+        const chain = await getChainMetadata(options.contract.chain);
+        // return the native currency of the chain
+        return NATIVE_CURRENCY_SCHEMA.parse(chain.nativeCurrency);
+      } catch {
+        // no-op, fall through to the default values below
+      }
+    }
+
+    return NATIVE_CURRENCY_SCHEMA.parse(options.contract.chain.nativeCurrency);
   }
 
   try {