add custom formatEther method

src/lib/formatters.ts

@@ -0,0 +1,30 @@
+
+import { BN } from "@polkadot/util";
+import { formatEther } from "viem";
+
+export function formatEtherAsString(wei: bigint | string | BN): string {
+  let weiBigInt: bigint;
+
+  if (typeof wei === "bigint") {
+    weiBigInt = wei;
+  } else if (typeof wei === "string") {
+    weiBigInt = BigInt(wei);
+  } else if (wei instanceof BN) {
+    weiBigInt = BigInt(wei.toString());
+  } else {
+    throw new Error("Invalid input type");
+  }
+
+  return formatEther(weiBigInt);
+}
+
+export function formatEtherAsNumber(wei: bigint | string | BN): number {
+  const etherBigInt = BigInt(formatEtherAsString(wei));
+  const MAX_SAFE_INTEGER_BIGINT = BigInt(Number.MAX_SAFE_INTEGER);
+
+  if (etherBigInt > MAX_SAFE_INTEGER_BIGINT || etherBigInt < -MAX_SAFE_INTEGER_BIGINT) {
+    throw new Error("Value is outside of safe integer bounds for JavaScript numbers");
+  }
+
+  return Number(etherBigInt);
+}