feat(eth): expose AnchorV4ProposalID method (#478)

Author: davidtaikocha

eth/taiko_api_backend.go

@@ -110,7 +110,7 @@ func (s *TaikoAPIBackend) getLastBlockByBatchId(batchID *big.Int) (*big.Int, err
 			break
 		}
 		// Decode the AnchorV4 calldata to fetch the proposal ID for comparison.
-		proposalID, err := anchorV4ProposalID(currentBlock.Transactions()[0].Data())
+		proposalID, err := AnchorV4ProposalID(currentBlock.Transactions()[0].Data())
 		if err != nil {
 			return nil, err
 		}
@@ -123,8 +123,8 @@ func (s *TaikoAPIBackend) getLastBlockByBatchId(batchID *big.Int) (*big.Int, err
 	return nil, ethereum.NotFound
 }
 
-// anchorV4ProposalID extracts the proposal ID encoded inside an AnchorV4 transaction's calldata.
-func anchorV4ProposalID(txData []byte) (*big.Int, error) {
+// AnchorV4ProposalID extracts the proposal ID encoded inside an AnchorV4 transaction's calldata.
+func AnchorV4ProposalID(txData []byte) (*big.Int, error) {
 	if len(txData) < len(taiko.AnchorV4Selector) {
 		return nil, fmt.Errorf("anchorV4 tx data too short: %d", len(txData))
 	}

eth/taiko_api_backend_test.go

@@ -15,7 +15,7 @@ func TestAnchorV4ProposalID(t *testing.T) {
 		t.Fatalf("failed to decode calldata: %v", err)
 	}
 
-	proposalID, err := anchorV4ProposalID(data)
+	proposalID, err := AnchorV4ProposalID(data)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -27,7 +27,7 @@ func TestAnchorV4ProposalID(t *testing.T) {
 }
 
 func TestAnchorV4ProposalIDInvalidData(t *testing.T) {
-	if _, err := anchorV4ProposalID([]byte{0x10, 0x0f}); err == nil {
+	if _, err := AnchorV4ProposalID([]byte{0x10, 0x0f}); err == nil {
 		t.Fatal("expected error for malformed calldata")
 	}
 }