Expose API to directly call HashStruct from EIP-712, without the full…

… TypedDataV4 domain

Signed-off-by: Peter Broadhurst <peter.broadhurst@kaleido.io>

pkg/eip712/typed_data_v4.go

@@ -1,4 +1,4 @@
-// Copyright © 2023 Kaleido, Inc.
+// Copyright © 2024 Kaleido, Inc.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -223,6 +223,11 @@ func encodeData(ctx context.Context, typeName string, v interface{}, allTypes Ty
 	return encoded, nil
 }
 
+// HashStruct allows hashing of an individual structure, without the EIP-712 domain
+func HashStruct(ctx context.Context, typeName string, v interface{}, allTypes TypeSet) (result ethtypes.HexBytes0xPrefix, err error) {
+	return hashStruct(ctx, typeName, v, allTypes, "")
+}
+
 func hashStruct(ctx context.Context, typeName string, v interface{}, allTypes TypeSet, breadcrumbs string) (result ethtypes.HexBytes0xPrefix, err error) {
 	encoded, err := encodeData(ctx, typeName, v, allTypes, breadcrumbs)
 	if err != nil {

pkg/eip712/typed_data_v4_test.go

@@ -82,6 +82,10 @@ func TestMessage_ExampleFromEIP712Spec(t *testing.T) {
 	ed, err := EncodeTypedDataV4(ctx, &p)
 	assert.NoError(t, err)
 	assert.Equal(t, "0xde26f53b35dd5ffdc13f8297e5cc7bbcb1a04bf33803bd2bf4a45eb251360cb8", ed.String())
+
+	hs, err := HashStruct(ctx, p.PrimaryType, p.Message, p.Types)
+	assert.NoError(t, err)
+	assert.Equal(t, "0xc52c0ee5d84264471806290a3f2c4cecfc5490626bf912d01f240d7a274b371e", hs.String())
 }
 
 func TestMessage_EmptyMessage(t *testing.T) {