From 77dc55af51b405fab839092efb8eac662e65cfdd Mon Sep 17 00:00:00 2001
From: Ryan Ghods <ryan@ryanio.com>
Date: Tue, 9 Mar 2021 15:29:35 -0800
Subject: [PATCH] introduce `common.copy()` for deep copy

---
 packages/client/lib/config.ts      | 4 ++--
 packages/common/src/index.ts       | 7 +++++++
 packages/tx/src/baseTransaction.ts | 5 +----
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/packages/client/lib/config.ts b/packages/client/lib/config.ts
index 639b3595e3..01fd275692 100644
--- a/packages/client/lib/config.ts
+++ b/packages/client/lib/config.ts
@@ -194,8 +194,8 @@ export class Config {
     // TODO: map chainParams (and lib/util.parseParams) to new Common format
     const common =
       options.common ?? new Common({ chain: Config.CHAIN_DEFAULT, hardfork: 'chainstart' })
-    this.chainCommon = Object.assign(Object.create(Object.getPrototypeOf(common)), common)
-    this.execCommon = Object.assign(Object.create(Object.getPrototypeOf(common)), common)
+    this.chainCommon = common.copy()
+    this.execCommon = common.copy()
 
     this.discDns = this.getDnsDiscovery(options.discDns)
     this.discV4 = this.getV4Discovery(options.discV4)
diff --git a/packages/common/src/index.ts b/packages/common/src/index.ts
index e131b494bc..dc462b7653 100644
--- a/packages/common/src/index.ts
+++ b/packages/common/src/index.ts
@@ -742,4 +742,11 @@ export default class Common extends EventEmitter {
   consensusConfig(): any {
     return (<any>this._chainParams)['consensus'][this.consensusAlgorithm()]
   }
+
+  /**
+   * Returns a deep copy of this common instance.
+   */
+  copy(): Common {
+    return Object.assign(Object.create(Object.getPrototypeOf(this)), this)
+  }
 }
diff --git a/packages/tx/src/baseTransaction.ts b/packages/tx/src/baseTransaction.ts
index 9bfd482ff5..36c2f749d5 100644
--- a/packages/tx/src/baseTransaction.ts
+++ b/packages/tx/src/baseTransaction.ts
@@ -46,10 +46,7 @@ export abstract class BaseTransaction<TransactionObject> {
 
     this._validateExceedsMaxInteger(validateCannotExceedMaxInteger)
 
-    this.common =
-      (txOptions.common &&
-        Object.assign(Object.create(Object.getPrototypeOf(txOptions.common)), txOptions.common)) ??
-      new Common({ chain: 'mainnet' })
+    this.common = txOptions.common?.copy() ?? new Common({ chain: 'mainnet' })
   }
 
   /**