tx: add getDataFee to tx cache

packages/tx/src/baseTransaction.ts

@@ -23,6 +23,7 @@ import {
 
 interface TransactionCache {
   hash: Buffer | undefined
+  dataFee: BN | undefined
 }
 
 /**
@@ -49,6 +50,7 @@ export abstract class BaseTransaction<TransactionObject> {
 
   protected cache: TransactionCache = {
     hash: undefined,
+    dataFee: undefined,
   }
 
   /**
@@ -185,6 +187,7 @@ export abstract class BaseTransaction<TransactionObject> {
     for (let i = 0; i < this.data.length; i++) {
       this.data[i] === 0 ? (cost += txDataZero) : (cost += txDataNonZero)
     }
+
     return new BN(cost)
   }
 

packages/tx/src/eip1559Transaction.ts

@@ -236,8 +236,17 @@ export default class FeeMarketEIP1559Transaction extends BaseTransaction<FeeMark
    * The amount of gas paid for the data in this tx
    */
   getDataFee(): BN {
+    if (Object.isFrozen(this) && this.cache.dataFee) {
+      return this.cache.dataFee
+    }
+
     const cost = super.getDataFee()
     cost.iaddn(AccessLists.getDataFeeEIP2930(this.accessList, this.common))
+
+    if (Object.isFrozen(this) && !this.cache.dataFee) {
+      this.cache.dataFee = cost
+    }
+
     return cost
   }
 

packages/tx/src/eip2930Transaction.ts

@@ -210,8 +210,17 @@ export default class AccessListEIP2930Transaction extends BaseTransaction<Access
    * The amount of gas paid for the data in this tx
    */
   getDataFee(): BN {
+    if (Object.isFrozen(this) && this.cache.dataFee) {
+      return this.cache.dataFee
+    }
+
     const cost = super.getDataFee()
     cost.iaddn(AccessLists.getDataFeeEIP2930(this.accessList, this.common))
+
+    if (Object.isFrozen(this) && !this.cache.dataFee) {
+      this.cache.dataFee = cost
+    }
+
     return cost
   }
 

packages/tx/src/legacyTransaction.ts

@@ -218,6 +218,19 @@ export default class Transaction extends BaseTransaction<Transaction> {
     }
   }
 
+  /**
+   * The amount of gas paid for the data in this tx
+   */
+  getDataFee(): BN {
+    if (Object.isFrozen(this)) {
+      if (!this.cache.dataFee) {
+        this.cache.dataFee = super.getDataFee()
+      }
+      return this.cache.dataFee
+    }
+    return super.getDataFee()
+  }
+
   /**
    * The up front amount that an account must have for this transaction to be valid
    */

packages/tx/test/eip1559.spec.ts

@@ -201,4 +201,14 @@ tape('[FeeMarketEIP1559Transaction]', function (t) {
     }, 'total fee must be the larger of the two')
     st.end()
   })
+
+  t.test('getDataFee()', function (st) {
+    let tx = FeeMarketEIP1559Transaction.fromTxData({}, { common })
+    st.ok(tx.getDataFee().toNumber() === 0, 'Should return data fee when frozen')
+
+    tx = FeeMarketEIP1559Transaction.fromTxData({}, { common, freeze: false })
+    st.ok(tx.getDataFee().toNumber() === 0, 'Should return data fee when not frozen')
+
+    st.end()
+  })
 })

packages/tx/test/legacy.spec.ts

@@ -152,6 +152,9 @@ tape('[Transaction]', function (t) {
     tx = Transaction.fromValuesArray(txFixtures[3].raw.map(toBuffer))
     st.equals(tx.getDataFee().toNumber(), 1716)
 
+    tx = Transaction.fromValuesArray(txFixtures[3].raw.map(toBuffer), { freeze: false })
+    st.equals(tx.getDataFee().toNumber(), 1716)
+
     st.end()
   })
 

packages/tx/test/typedTxsAndEIP2930.spec.ts

@@ -528,4 +528,14 @@ tape('[AccessListEIP2930Transaction] -> Class Specific Tests', function (t) {
 
     t.end()
   })
+
+  t.test('getDataFee()', function (st) {
+    let tx = AccessListEIP2930Transaction.fromTxData({}, { common })
+    st.ok(tx.getDataFee().toNumber() === 0, 'Should return data fee when frozen')
+
+    tx = AccessListEIP2930Transaction.fromTxData({}, { common, freeze: false })
+    st.ok(tx.getDataFee().toNumber() === 0, 'Should return data fee when not frozen')
+
+    st.end()
+  })
 })