feature: add alert when wallet is not connected

Author: Lena Hierzi

example-frontend/pages/autoOffsetExactInETH.tsx

@@ -22,6 +22,10 @@ export default function AutoOffsetExactInETH() {
   );
   // retire carbon credits using native tokens e.g., MATIC, specifying the exact amount of TCO2s to retire (only on Polygon, not on Celo),
   const offset = async () => {
+    if (!signer) {
+      alert("Please Connect your Wallet.");
+    }
+
     try {
       const result = await offsetHelper.autoOffsetExactInETH(poolAddress, {
         value: amount,

example-frontend/pages/autoOffsetExactInToken.tsx

@@ -31,6 +31,10 @@ export default function AutoOffsetExactInToken() {
     signer || provider
   );
   const offset = async () => {
+    if (!signer) {
+      alert("Please Connect your Wallet.");
+    }
+
     try {
       // approve spending of deposited tokens
       await (

example-frontend/pages/autoOffsetExactOutETH.tsx

@@ -21,6 +21,10 @@ export default function AutoOffsetExactOutETH() {
     signer || provider
   );
   const offset = async () => {
+    if (!signer) {
+      alert("Please Connect your Wallet.");
+    }
+
     try {
       // determine how much native tokens e.g., MATIC, token must be sent
       const amountOut = await offsetHelper.calculateNeededETHAmount(

example-frontend/pages/autoOffsetExactOutToken.tsx

@@ -34,6 +34,10 @@ export default function AutoOffsetExactOutToken() {
     signer || provider
   );
   const offset = async () => {
+    if (!signer) {
+      alert("Please Connect your Wallet.");
+    }
+
     try {
       // determine how much of the ERC20 token must be sent
       const amountOut = await offsetHelper.calculateNeededTokenAmount(

example-frontend/pages/autoOffsetPoolToken.tsx

@@ -29,6 +29,10 @@ export default function AutoOffsetPoolToken() {
   );
 
   const offset = async () => {
+    if (!signer) {
+      alert("Please Connect your Wallet.");
+    }
+
     try {
       // approve spending of pool tokens
       await (await poolToken.approve(offsetHelper.address, amount)).wait();