Create util module and move batch check in there

packages/core/src/publicCredential/PublicCredential.chain.ts

@@ -32,6 +32,7 @@ import { validateUri } from '@kiltprotocol/asset-did'
 import { SDKErrors } from '@kiltprotocol/utils'
 
 import { getIdForCredential } from './PublicCredential.js'
+import isBatch from '../utils.js'
 
 export interface EncodedPublicCredential {
   ctypeHash: CTypeHash
@@ -199,11 +200,7 @@ export async function credentialFromChain(
     submitter = extrinsicDidOrigin
   }
   // ... or a utility::{batch,batch_all,force_batch} extrinsic which include a DID-authorized call
-  else if (
-    api.tx.utility.batch.is(extrinsic) ||
-    api.tx.utility.batchAll.is(extrinsic) ||
-    api.tx.utility.forceBatch.is(extrinsic)
-  ) {
+  else if (isBatch(extrinsic)) {
     // From the batch, only consider did::submit_did calls
     const didCalls = extrinsic.args[0].flatMap((batchCall) =>
       extractDidCallsFromBatchCall(api, batchCall)

packages/core/src/utils.ts

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2018-2022, BOTLabs GmbH.
+ *
+ * This source code is licensed under the BSD 4-Clause "Original" license
+ * found in the LICENSE file in the root directory of this source tree.
+ */
+
+import type { Extrinsic } from '@polkadot/types/interfaces'
+
+import { ConfigService } from '@kiltprotocol/config'
+import { GenericExtrinsic } from '@polkadot/types'
+
+/**
+ * Checks wheather the provided extrinsic is one of the potential batch extrinsics.
+ *
+ * @param extrinsic The input [[Extrinsic]].
+ *
+ * @returns True if the extrinsic is a batch extrinsic, false otherwise.
+ */
+export function isBatch(
+  extrinsic: Extrinsic
+): extrinsic is GenericExtrinsic<
+  | typeof api.tx.utility.batch.args
+  | typeof api.tx.utility.batchAll.args
+  | typeof api.tx.utility.forceBatch.args
+> {
+  const api = ConfigService.get('api')
+
+  return (
+    api.tx.utility.batch.is(extrinsic) ||
+    api.tx.utility.batchAll.is(extrinsic) ||
+    api.tx.utility.forceBatch.is(extrinsic)
+  )
+}