added fee calcualate

src/components/utils/cosmos-client.js

@@ -1,4 +1,8 @@
 import { SigningCosmWasmClient, CosmWasmClient } from '@cosmjs/cosmwasm-stargate'
+import { Uint53 } from "@cosmjs/math";
+import {
+    GasPrice, coins
+} from "@cosmjs/stargate";
 export async function createClient(rpcUrl, offlineSigner) {
     const client = SigningCosmWasmClient.connectWithSigner(
         rpcUrl,
@@ -12,3 +16,15 @@ export async function createNonSigningClient(rpcUrl) {
     return client
 }
 
+export function calculateFee(gasLimit, gasPrice) {
+    const processedGasPrice = typeof gasPrice === "string" ? GasPrice.fromString(gasPrice) : gasPrice;
+    const { denom, amount: gasPriceAmount } = processedGasPrice;
+    // Note: Amount can exceed the safe integer range (https://github.com/cosmos/cosmjs/issues/1134),
+    // which we handle by converting from Decimal to string without going through number.
+    const t = gasPriceAmount.multiply(new Uint53(gasLimit))
+    const amount = t.toString();
+    return {
+        amount: coins(amount, denom),
+        gas: gasLimit.toString(),
+    };
+}