feat: add getEstimatedFee to Transaction (#23579)

web3.js/src/transaction.ts

@@ -2,6 +2,7 @@ import nacl from 'tweetnacl';
 import bs58 from 'bs58';
 import {Buffer} from 'buffer';
 
+import {Connection} from './connection';
 import {Message} from './message';
 import {PublicKey} from './publickey';
 import * as shortvec from './util/shortvec-encoding';
@@ -405,6 +406,13 @@ export class Transaction {
     return this._compile().serialize();
   }
 
+  /**
+   * Get the estimated fee associated with a transaction
+   */
+  async getEstimatedFee(connection: Connection): Promise<number> {
+    return (await connection.getFeeForMessage(this.compileMessage())).value;
+  }
+
   /**
    * Specify the public keys which will be used to sign the Transaction.
    * The first signer will be used as the transaction fee payer account.