From ecaaa92497cc9f94f25e027ab2399930a9fc051e Mon Sep 17 00:00:00 2001
From: pritsheth <prit.sheth@stellar.org>
Date: Fri, 10 May 2024 12:02:51 -0700
Subject: [PATCH 01/10] Add stateDiff in SimulateTransaction API response

---
 src/soroban/api.ts                            | 20 ++++++++++++--
 .../soroban/simulate_transaction_test.js      | 27 +++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/soroban/api.ts b/src/soroban/api.ts
index 3c8d7806f..d64fc951a 100644
--- a/src/soroban/api.ts
+++ b/src/soroban/api.ts
@@ -175,8 +175,18 @@ export namespace Api {
     value: string;
   }
 
-  export interface RequestAirdropResponse {
-    transaction_id: string;
+  interface RawLedgerEntryDiff {
+    type: number;
+    key: string;
+    before?: string;
+    after?: string;
+  }
+
+  interface LedgerEntryDiff{
+    type: number;
+    key: string;
+    before?: xdr.LedgerEntry;
+    after?: xdr.LedgerEntry;
   }
 
   export type SendTransactionStatus =
@@ -264,6 +274,9 @@ export namespace Api {
 
     /** present only for invocation simulation */
     result?: SimulateHostFunctionResult;
+
+    // State Difference information
+    stateDiff?: LedgerEntryDiff[];
   }
 
   /** Includes details about why the simulation failed */
@@ -347,5 +360,8 @@ export namespace Api {
       minResourceFee: string;
       transactionData: string;
     };
+
+    // State Difference information
+    stateDiff?: RawLedgerEntryDiff[];
   }
 }
diff --git a/test/unit/server/soroban/simulate_transaction_test.js b/test/unit/server/soroban/simulate_transaction_test.js
index f1c2bacbc..87f6f8bbe 100644
--- a/test/unit/server/soroban/simulate_transaction_test.js
+++ b/test/unit/server/soroban/simulate_transaction_test.js
@@ -32,6 +32,18 @@ describe("Server#simulateTransaction", async function (done) {
       retval: xdr.ScVal.fromXDR(simulationResponse.results[0].xdr, "base64"),
     },
     cost: simulationResponse.cost,
+    stateDiff: [{
+      type:1,
+      key: 'example-key',
+      before: new xdr.LedgerEntry({
+        lastModifiedLedgerSeq: 0,
+        ext: new xdr.LedgerEntryExt(0),
+      }),
+      after: new xdr.LedgerEntry({
+        lastModifiedLedgerSeq: 0,
+        ext: new xdr.LedgerEntryExt(0),
+      }),
+    }],
     _parsed: true,
   };
 
@@ -175,6 +187,7 @@ describe("Server#simulateTransaction", async function (done) {
     delete expected.cost;
     delete expected.transactionData;
     delete expected.minResourceFee;
+    delete expected.stateDiff
     expected.error = "This is an error";
     expected.events = [];
 
@@ -200,6 +213,7 @@ function cloneSimulation(sim) {
       retval: xdr.ScVal.fromXDR(sim.result.retval.toXDR()),
     },
     cost: sim.cost,
+    stateDiff: sim.stateDiff,
     _parsed: sim._parsed,
   };
 }
@@ -262,6 +276,19 @@ function baseSimulationResponse(results) {
       cpuInsns: "1",
       memBytes: "2",
     },
+    stateDiff:[{
+      type:1,
+      key: 'example-key',
+      before: new xdr.LedgerEntry({
+        lastModifiedLedgerSeq: 0,
+        ext: new xdr.LedgerEntryExt(0),
+      }).toXDR('base64'),
+      after: new xdr.LedgerEntry({
+        lastModifiedLedgerSeq: 0,
+        ext: new xdr.LedgerEntryExt(0),
+      }).toXDR('base64'),
+    }],
+
   };
 }
 

From 33985fcb3833ca2814ddb31ebe72d67ae8fc0271 Mon Sep 17 00:00:00 2001
From: pritsheth <prit.sheth@stellar.org>
Date: Fri, 10 May 2024 13:24:26 -0700
Subject: [PATCH 02/10] Add parsing of stateDiff

---
 src/soroban/api.ts     |  2 ++
 src/soroban/parsers.ts | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/soroban/api.ts b/src/soroban/api.ts
index d64fc951a..af73abb61 100644
--- a/src/soroban/api.ts
+++ b/src/soroban/api.ts
@@ -178,7 +178,9 @@ export namespace Api {
   interface RawLedgerEntryDiff {
     type: number;
     key: string;
+    // these are xdr.LedgerEntry in base64
     before?: string;
+    // these are xdr.LedgerEntry in base64
     after?: string;
   }
 
diff --git a/src/soroban/parsers.ts b/src/soroban/parsers.ts
index 8ff1d1c6d..26a9b666f 100644
--- a/src/soroban/parsers.ts
+++ b/src/soroban/parsers.ts
@@ -139,7 +139,18 @@ function parseSuccessful(
             : xdr.ScVal.scvVoid()
         };
       })[0]
-    })
+    }),
+
+    stateDiff: sim.stateDiff?.length ?? 0 > 0
+        ? sim.stateDiff!.map((entryDiff) => {
+          return {
+            type: entryDiff.type,
+            key: entryDiff.key,
+            before: xdr.LedgerEntry.fromXDR(entryDiff.before, 'base64'),
+            after: xdr.LedgerEntry.fromXDR(entryDiff.after, 'base64'),
+          };
+        })
+        : null,
   };
 
   if (!sim.restorePreamble || sim.restorePreamble.transactionData === '') {

From 84eda50d2b9bbadd4c17e1602dc089c1dde9a803 Mon Sep 17 00:00:00 2001
From: pritsheth <prit.sheth@stellar.org>
Date: Fri, 10 May 2024 13:37:44 -0700
Subject: [PATCH 03/10] Fix undefined type issues

---
 src/soroban/parsers.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/soroban/parsers.ts b/src/soroban/parsers.ts
index 26a9b666f..b734632b5 100644
--- a/src/soroban/parsers.ts
+++ b/src/soroban/parsers.ts
@@ -146,11 +146,11 @@ function parseSuccessful(
           return {
             type: entryDiff.type,
             key: entryDiff.key,
-            before: xdr.LedgerEntry.fromXDR(entryDiff.before, 'base64'),
-            after: xdr.LedgerEntry.fromXDR(entryDiff.after, 'base64'),
+            before: !!entryDiff.before ? xdr.LedgerEntry.fromXDR(entryDiff.before, 'base64') : undefined,
+            after: !!entryDiff.after ? xdr.LedgerEntry.fromXDR(entryDiff.after, 'base64') : undefined,
           };
         })
-        : null,
+        : undefined,
   };
 
   if (!sim.restorePreamble || sim.restorePreamble.transactionData === '') {

From 297525ac3bd6c0ff6cb515e8769676bcc17123f0 Mon Sep 17 00:00:00 2001
From: pritsheth <prit.sheth@stellar.org>
Date: Mon, 13 May 2024 09:28:36 -0700
Subject: [PATCH 04/10] Update key type in LedgerEntryDiff

---
 src/soroban/api.ts                            |  3 +-
 src/soroban/parsers.ts                        |  2 +-
 test/unit/server/soroban/get_account_test.js  |  4 +-
 test/unit/server/soroban/get_events_test.js   |  8 +--
 .../server/soroban/get_ledger_entries_test.js |  2 +-
 .../soroban/simulate_transaction_test.js      | 55 ++++++++++---------
 6 files changed, 39 insertions(+), 35 deletions(-)

diff --git a/src/soroban/api.ts b/src/soroban/api.ts
index af73abb61..75f9e4a1c 100644
--- a/src/soroban/api.ts
+++ b/src/soroban/api.ts
@@ -177,6 +177,7 @@ export namespace Api {
 
   interface RawLedgerEntryDiff {
     type: number;
+    // This is LedgerKey in base64
     key: string;
     // these are xdr.LedgerEntry in base64
     before?: string;
@@ -186,7 +187,7 @@ export namespace Api {
 
   interface LedgerEntryDiff{
     type: number;
-    key: string;
+    key: xdr.LedgerKey;
     before?: xdr.LedgerEntry;
     after?: xdr.LedgerEntry;
   }
diff --git a/src/soroban/parsers.ts b/src/soroban/parsers.ts
index b734632b5..61d5740db 100644
--- a/src/soroban/parsers.ts
+++ b/src/soroban/parsers.ts
@@ -145,7 +145,7 @@ function parseSuccessful(
         ? sim.stateDiff!.map((entryDiff) => {
           return {
             type: entryDiff.type,
-            key: entryDiff.key,
+            key: xdr.LedgerKey.fromXDR(entryDiff.key, 'base64'),
             before: !!entryDiff.before ? xdr.LedgerEntry.fromXDR(entryDiff.before, 'base64') : undefined,
             after: !!entryDiff.after ? xdr.LedgerEntry.fromXDR(entryDiff.after, 'base64') : undefined,
           };
diff --git a/test/unit/server/soroban/get_account_test.js b/test/unit/server/soroban/get_account_test.js
index b6781f76c..8258291d3 100644
--- a/test/unit/server/soroban/get_account_test.js
+++ b/test/unit/server/soroban/get_account_test.js
@@ -25,7 +25,7 @@ describe("Server#getAccount", function () {
         jsonrpc: "2.0",
         id: 1,
         method: "getLedgerEntries",
-        params: { keys: [ key.toXDR("base64") ] },
+        params: { keys: [key.toXDR("base64")] },
       })
       .returns(
         Promise.resolve({
@@ -62,7 +62,7 @@ describe("Server#getAccount", function () {
         jsonrpc: "2.0",
         id: 1,
         method: "getLedgerEntries",
-        params: { keys: [ key.toXDR("base64") ] },
+        params: { keys: [key.toXDR("base64")] },
       })
       .returns(
         Promise.resolve({
diff --git a/test/unit/server/soroban/get_events_test.js b/test/unit/server/soroban/get_events_test.js
index 8b3f4f8e7..f6de7132d 100644
--- a/test/unit/server/soroban/get_events_test.js
+++ b/test/unit/server/soroban/get_events_test.js
@@ -246,7 +246,7 @@ let getEventsResponseFixture = [
     inSuccessfulContractCall: true,
     topic: topicVals.slice(0, 2),
     value: eventVal,
-    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c"
+    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c",
   },
   {
     type: "contract",
@@ -258,7 +258,7 @@ let getEventsResponseFixture = [
     inSuccessfulContractCall: true,
     topic: topicVals.slice(0, 2),
     value: eventVal,
-    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c"
+    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c",
   },
   {
     type: "diagnostic",
@@ -270,7 +270,7 @@ let getEventsResponseFixture = [
     inSuccessfulContractCall: true,
     topic: [topicVals[0]],
     value: eventVal,
-    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c"
+    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c",
   },
   {
     type: "contract",
@@ -282,6 +282,6 @@ let getEventsResponseFixture = [
     inSuccessfulContractCall: true,
     topic: topicVals,
     value: eventVal,
-    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c"
+    txHash: "d7d09af2ca4f2929ee701cf86d05e4ca5f849a726d0db344785a8f9894e79e6c",
   },
 ];
diff --git a/test/unit/server/soroban/get_ledger_entries_test.js b/test/unit/server/soroban/get_ledger_entries_test.js
index cf11dc5f3..4adda2d3c 100644
--- a/test/unit/server/soroban/get_ledger_entries_test.js
+++ b/test/unit/server/soroban/get_ledger_entries_test.js
@@ -44,7 +44,7 @@ describe("Server#getLedgerEntries", function () {
         jsonrpc: "2.0",
         id: 1,
         method: "getLedgerEntries",
-        params: {keys: requests},
+        params: { keys: requests },
       })
       .returns(
         Promise.resolve({
diff --git a/test/unit/server/soroban/simulate_transaction_test.js b/test/unit/server/soroban/simulate_transaction_test.js
index 87f6f8bbe..2bff0ff88 100644
--- a/test/unit/server/soroban/simulate_transaction_test.js
+++ b/test/unit/server/soroban/simulate_transaction_test.js
@@ -32,18 +32,20 @@ describe("Server#simulateTransaction", async function (done) {
       retval: xdr.ScVal.fromXDR(simulationResponse.results[0].xdr, "base64"),
     },
     cost: simulationResponse.cost,
-    stateDiff: [{
-      type:1,
-      key: 'example-key',
-      before: new xdr.LedgerEntry({
-        lastModifiedLedgerSeq: 0,
-        ext: new xdr.LedgerEntryExt(0),
-      }),
-      after: new xdr.LedgerEntry({
-        lastModifiedLedgerSeq: 0,
-        ext: new xdr.LedgerEntryExt(0),
-      }),
-    }],
+    stateDiff: [
+      {
+        type: 1,
+        key: "example-key",
+        before: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          ext: new xdr.LedgerEntryExt(0),
+        }),
+        after: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          ext: new xdr.LedgerEntryExt(0),
+        }),
+      },
+    ],
     _parsed: true,
   };
 
@@ -187,7 +189,7 @@ describe("Server#simulateTransaction", async function (done) {
     delete expected.cost;
     delete expected.transactionData;
     delete expected.minResourceFee;
-    delete expected.stateDiff
+    delete expected.stateDiff;
     expected.error = "This is an error";
     expected.events = [];
 
@@ -276,19 +278,20 @@ function baseSimulationResponse(results) {
       cpuInsns: "1",
       memBytes: "2",
     },
-    stateDiff:[{
-      type:1,
-      key: 'example-key',
-      before: new xdr.LedgerEntry({
-        lastModifiedLedgerSeq: 0,
-        ext: new xdr.LedgerEntryExt(0),
-      }).toXDR('base64'),
-      after: new xdr.LedgerEntry({
-        lastModifiedLedgerSeq: 0,
-        ext: new xdr.LedgerEntryExt(0),
-      }).toXDR('base64'),
-    }],
-
+    stateDiff: [
+      {
+        type: 1,
+        key: "example-key",
+        before: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          ext: new xdr.LedgerEntryExt(0),
+        }).toXDR("base64"),
+        after: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          ext: new xdr.LedgerEntryExt(0),
+        }).toXDR("base64"),
+      },
+    ],
   };
 }
 

From 0263f61f78d55462ea9779aa7fcdbcc85ef726bf Mon Sep 17 00:00:00 2001
From: pritsheth <prit.sheth@stellar.org>
Date: Wed, 15 May 2024 11:16:56 -0700
Subject: [PATCH 05/10] Rename stateDiff to stateChanges

---
 src/soroban/api.ts                                   |  8 ++++----
 src/soroban/parsers.ts                               | 12 ++++++------
 .../unit/server/soroban/simulate_transaction_test.js |  8 ++++----
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/soroban/api.ts b/src/soroban/api.ts
index 75f9e4a1c..e270bd066 100644
--- a/src/soroban/api.ts
+++ b/src/soroban/api.ts
@@ -175,7 +175,7 @@ export namespace Api {
     value: string;
   }
 
-  interface RawLedgerEntryDiff {
+  interface RawLedgerEntryChange {
     type: number;
     // This is LedgerKey in base64
     key: string;
@@ -185,7 +185,7 @@ export namespace Api {
     after?: string;
   }
 
-  interface LedgerEntryDiff{
+  interface LedgerEntryChange{
     type: number;
     key: xdr.LedgerKey;
     before?: xdr.LedgerEntry;
@@ -279,7 +279,7 @@ export namespace Api {
     result?: SimulateHostFunctionResult;
 
     // State Difference information
-    stateDiff?: LedgerEntryDiff[];
+    stateChanges?: LedgerEntryChange[];
   }
 
   /** Includes details about why the simulation failed */
@@ -365,6 +365,6 @@ export namespace Api {
     };
 
     // State Difference information
-    stateDiff?: RawLedgerEntryDiff[];
+    stateChanges?: RawLedgerEntryChange[];
   }
 }
diff --git a/src/soroban/parsers.ts b/src/soroban/parsers.ts
index 61d5740db..1900f310d 100644
--- a/src/soroban/parsers.ts
+++ b/src/soroban/parsers.ts
@@ -141,13 +141,13 @@ function parseSuccessful(
       })[0]
     }),
 
-    stateDiff: sim.stateDiff?.length ?? 0 > 0
-        ? sim.stateDiff!.map((entryDiff) => {
+    stateChanges: sim.stateChanges?.length ?? 0 > 0
+        ? sim.stateChanges!.map((entryChange) => {
           return {
-            type: entryDiff.type,
-            key: xdr.LedgerKey.fromXDR(entryDiff.key, 'base64'),
-            before: !!entryDiff.before ? xdr.LedgerEntry.fromXDR(entryDiff.before, 'base64') : undefined,
-            after: !!entryDiff.after ? xdr.LedgerEntry.fromXDR(entryDiff.after, 'base64') : undefined,
+            type: entryChange.type,
+            key: xdr.LedgerKey.fromXDR(entryChange.key, 'base64'),
+            before: !!entryChange.before ? xdr.LedgerEntry.fromXDR(entryChange.before, 'base64') : undefined,
+            after: !!entryChange.after ? xdr.LedgerEntry.fromXDR(entryChange.after, 'base64') : undefined,
           };
         })
         : undefined,
diff --git a/test/unit/server/soroban/simulate_transaction_test.js b/test/unit/server/soroban/simulate_transaction_test.js
index 2bff0ff88..5abe52fb5 100644
--- a/test/unit/server/soroban/simulate_transaction_test.js
+++ b/test/unit/server/soroban/simulate_transaction_test.js
@@ -32,7 +32,7 @@ describe("Server#simulateTransaction", async function (done) {
       retval: xdr.ScVal.fromXDR(simulationResponse.results[0].xdr, "base64"),
     },
     cost: simulationResponse.cost,
-    stateDiff: [
+    stateChanges: [
       {
         type: 1,
         key: "example-key",
@@ -189,7 +189,7 @@ describe("Server#simulateTransaction", async function (done) {
     delete expected.cost;
     delete expected.transactionData;
     delete expected.minResourceFee;
-    delete expected.stateDiff;
+    delete expected.stateChanges;
     expected.error = "This is an error";
     expected.events = [];
 
@@ -215,7 +215,7 @@ function cloneSimulation(sim) {
       retval: xdr.ScVal.fromXDR(sim.result.retval.toXDR()),
     },
     cost: sim.cost,
-    stateDiff: sim.stateDiff,
+    stateChanges: sim.stateChanges,
     _parsed: sim._parsed,
   };
 }
@@ -278,7 +278,7 @@ function baseSimulationResponse(results) {
       cpuInsns: "1",
       memBytes: "2",
     },
-    stateDiff: [
+    stateChanges: [
       {
         type: 1,
         key: "example-key",

From 07e4c610980ed8f0b1b3c4c692f50c58b5aa817e Mon Sep 17 00:00:00 2001
From: Prit Sheth <prit.sheth@stellar.org>
Date: Fri, 17 May 2024 00:06:59 -0700
Subject: [PATCH 06/10] Fix review comments and add more tests

---
 src/soroban/api.ts                            |  40 +++----
 src/soroban/parsers.ts                        |   6 +-
 .../soroban/simulate_transaction_test.js      | 112 ++++++++++++++++--
 3 files changed, 123 insertions(+), 35 deletions(-)

diff --git a/src/soroban/api.ts b/src/soroban/api.ts
index e270bd066..f9dabc306 100644
--- a/src/soroban/api.ts
+++ b/src/soroban/api.ts
@@ -3,13 +3,6 @@ import { AssetType, Contract, SorobanDataBuilder, xdr } from '@stellar/stellar-b
 /* tslint:disable-next-line:no-namespace */
 /** @namespace Api */
 export namespace Api {
-  export interface Balance {
-    asset_type: AssetType.credit4 | AssetType.credit12;
-    asset_code: string;
-    asset_issuer: string;
-    classic: string;
-    smart: string;
-  }
 
   export interface Cost {
     cpuInsns: string;
@@ -175,21 +168,21 @@ export namespace Api {
     value: string;
   }
 
-  interface RawLedgerEntryChange {
+  export interface RawLedgerEntryChange {
     type: number;
-    // This is LedgerKey in base64
+    /** This is LedgerKey in base64 */
     key: string;
-    // these are xdr.LedgerEntry in base64
-    before?: string;
-    // these are xdr.LedgerEntry in base64
-    after?: string;
+    /** This is xdr.LedgerEntry in base64 */
+    before: string | null;
+    /** This is xdr.LedgerEntry in base64 */
+    after: string | null;
   }
 
-  interface LedgerEntryChange{
+  export interface LedgerEntryChange{
     type: number;
     key: xdr.LedgerKey;
-    before?: xdr.LedgerEntry;
-    after?: xdr.LedgerEntry;
+    before: xdr.LedgerEntry | null;
+    after: xdr.LedgerEntry | null;
   }
 
   export type SendTransactionStatus =
@@ -278,7 +271,7 @@ export namespace Api {
     /** present only for invocation simulation */
     result?: SimulateHostFunctionResult;
 
-    // State Difference information
+    /** State Difference information */
     stateChanges?: LedgerEntryChange[];
   }
 
@@ -349,22 +342,23 @@ export namespace Api {
     id: string;
     latestLedger: number;
     error?: string;
-    // this is an xdr.SorobanTransactionData in base64
+    /** This is an xdr.SorobanTransactionData in base64 */
     transactionData?: string;
-    // these are xdr.DiagnosticEvents in base64
+    /** These are xdr.DiagnosticEvents in base64 */
     events?: string[];
     minResourceFee?: string;
-    // This will only contain a single element if present, because only a single
-    // invokeHostFunctionOperation is supported per transaction.
+    /** This will only contain a single element if present, because only a single
+     * invokeHostFunctionOperation is supported per transaction.
+     * */
     results?: RawSimulateHostFunctionResult[];
     cost?: Cost;
-    // present if succeeded but has expired ledger entries
+    /** Present if succeeded but has expired ledger entries */
     restorePreamble?: {
       minResourceFee: string;
       transactionData: string;
     };
 
-    // State Difference information
+    /** State Difference information */
     stateChanges?: RawLedgerEntryChange[];
   }
 }
diff --git a/src/soroban/parsers.ts b/src/soroban/parsers.ts
index 1900f310d..1838556ab 100644
--- a/src/soroban/parsers.ts
+++ b/src/soroban/parsers.ts
@@ -142,12 +142,12 @@ function parseSuccessful(
     }),
 
     stateChanges: sim.stateChanges?.length ?? 0 > 0
-        ? sim.stateChanges!.map((entryChange) => {
+        ? sim.stateChanges.map((entryChange) => {
           return {
             type: entryChange.type,
             key: xdr.LedgerKey.fromXDR(entryChange.key, 'base64'),
-            before: !!entryChange.before ? xdr.LedgerEntry.fromXDR(entryChange.before, 'base64') : undefined,
-            after: !!entryChange.after ? xdr.LedgerEntry.fromXDR(entryChange.after, 'base64') : undefined,
+            before: entryChange.before ? xdr.LedgerEntry.fromXDR(entryChange.before, 'base64') : null,
+            after: entryChange.after ? xdr.LedgerEntry.fromXDR(entryChange.after, 'base64') : null,
           };
         })
         : undefined,
diff --git a/test/unit/server/soroban/simulate_transaction_test.js b/test/unit/server/soroban/simulate_transaction_test.js
index 5abe52fb5..68e2b7dbc 100644
--- a/test/unit/server/soroban/simulate_transaction_test.js
+++ b/test/unit/server/soroban/simulate_transaction_test.js
@@ -34,15 +34,17 @@ describe("Server#simulateTransaction", async function (done) {
     cost: simulationResponse.cost,
     stateChanges: [
       {
-        type: 1,
-        key: "example-key",
+        type: 2,
+        key: "example-key-2",
         before: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
-          ext: new xdr.LedgerEntryExt(0),
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
         }),
         after: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
-          ext: new xdr.LedgerEntryExt(0),
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
         }),
       },
     ],
@@ -180,6 +182,53 @@ describe("Server#simulateTransaction", async function (done) {
     );
   });
 
+  it("works with state changes", async function () {
+    return invokeSimulationResponseWithStateChanges(address).then(
+        (simResponse) => {
+          const expected = cloneSimulation(parsedSimulationResponse);
+          expected.stateChanges = [
+            {
+              type: 2,
+              key: "example-key-2",
+              before: new xdr.LedgerEntry({
+                lastModifiedLedgerSeq: 0,
+                data: new xdr.LedgerEntryData(),
+                ext: new xdr.LedgerEntryExt(),
+              }),
+              after: new xdr.LedgerEntry({
+                lastModifiedLedgerSeq: 0,
+                data: new xdr.LedgerEntryData(),
+                ext: new xdr.LedgerEntryExt(),
+              }),
+            },
+            {
+              type: 1,
+              key: "example-key-1",
+              before: null,
+              after: new xdr.LedgerEntry({
+                lastModifiedLedgerSeq: 0,
+                data: new xdr.LedgerEntryData(),
+                ext: new xdr.LedgerEntryExt(),
+              }),
+            },
+            {
+              type: 3,
+              key: "example-key-3",
+              before: new xdr.LedgerEntry({
+                lastModifiedLedgerSeq: 0,
+                data: new xdr.LedgerEntryData(),
+                ext: new xdr.LedgerEntryExt(),
+              }),
+              after: null,
+            },
+          ]
+
+          const parsed = parseRawSimulation(simResponse);
+          expect(parsed).to.be.deep.equal(expected);
+        },
+    );
+  });
+
   it("works with errors", function () {
     let simResponse = simulationResponseError();
 
@@ -280,17 +329,19 @@ function baseSimulationResponse(results) {
     },
     stateChanges: [
       {
-        type: 1,
-        key: "example-key",
+        type: 2,
+        key: "example-key-2",
         before: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
-          ext: new xdr.LedgerEntryExt(0),
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
         }).toXDR("base64"),
         after: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
-          ext: new xdr.LedgerEntryExt(0),
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
         }).toXDR("base64"),
-      },
+      }
     ],
   };
 }
@@ -305,6 +356,49 @@ async function invokeSimulationResponseWithRestoration(address) {
   };
 }
 
+async function invokeSimulationResponseWithStateChanges(address) {
+  return {
+    ...(await invokeSimulationResponse(address)),
+    stateChanges: [
+      {
+        type: 2,
+        key: "example-key-2",
+        before: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
+        }).toXDR("base64"),
+        after: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
+        }).toXDR("base64"),
+      },
+      {
+        type: 1,
+        key: "example-key-1",
+        before: null,
+        after: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
+        }).toXDR("base64"),
+      },
+      {
+        type: 3,
+        key: "example-key-3",
+        before: new xdr.LedgerEntry({
+          lastModifiedLedgerSeq: 0,
+          data: new xdr.LedgerEntryData(),
+          ext: new xdr.LedgerEntryExt(),
+        }).toXDR("base64"),
+        after: null,
+      },
+    ],
+  };
+}
+
+
 describe("works with real responses", function () {
   const schema = {
     transactionData:

From 010bf92770b665097ccfbb0b9d918005f7c1be31 Mon Sep 17 00:00:00 2001
From: Prit Sheth <prit.sheth@stellar.org>
Date: Fri, 17 May 2024 13:50:52 -0700
Subject: [PATCH 07/10] Update CHANGELOG.md

---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b3de9988b..067519b0a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ A breaking change will get clearly marked in this log.
 
 ## Unreleased
 
+Added:
+
+- Add stateChanges in SimulateTransaction API response ([#963](https://github.com/stellar/js-stellar-sdk/pull/963))
+
 
 ## [v12.0.0](https://github.com/stellar/js-stellar-sdk/compare/v11.3.0...v12.0.0)
 

From 7698a58d43ef4cdec6e7252635e111d1c4b8675f Mon Sep 17 00:00:00 2001
From: Prit Sheth <prit.sheth@stellar.org>
Date: Fri, 17 May 2024 13:57:43 -0700
Subject: [PATCH 08/10] Fix tests

---
 src/rpc/api.ts     | 2 +-
 src/rpc/parsers.ts | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/rpc/api.ts b/src/rpc/api.ts
index f9dabc306..cbfb8e442 100644
--- a/src/rpc/api.ts
+++ b/src/rpc/api.ts
@@ -1,4 +1,4 @@
-import { AssetType, Contract, SorobanDataBuilder, xdr } from '@stellar/stellar-base';
+import { Contract, SorobanDataBuilder, xdr } from '@stellar/stellar-base';
 
 /* tslint:disable-next-line:no-namespace */
 /** @namespace Api */
diff --git a/src/rpc/parsers.ts b/src/rpc/parsers.ts
index 1838556ab..16be6fa71 100644
--- a/src/rpc/parsers.ts
+++ b/src/rpc/parsers.ts
@@ -142,7 +142,7 @@ function parseSuccessful(
     }),
 
     stateChanges: sim.stateChanges?.length ?? 0 > 0
-        ? sim.stateChanges.map((entryChange) => {
+        ? sim.stateChanges?.map((entryChange) => {
           return {
             type: entryChange.type,
             key: xdr.LedgerKey.fromXDR(entryChange.key, 'base64'),

From 47272499235c161158ef80eb9d663f0665655701 Mon Sep 17 00:00:00 2001
From: Prit Sheth <prit.sheth@stellar.org>
Date: Wed, 29 May 2024 13:01:02 -0700
Subject: [PATCH 09/10] Fix review comments

---
 CHANGELOG.md                                  | 16 ++++++-
 src/rpc/api.ts                                |  2 +-
 .../soroban/simulate_transaction_test.js      | 45 +++++++++++++++----
 3 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a491aad86..9176304d9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,9 +8,23 @@ A breaking change will get clearly marked in this log.
 
 Added:
 
-- Add stateChanges in SimulateTransaction API response ([#963](https://github.com/stellar/js-stellar-sdk/pull/963))
+- `rpc.server.simulateTransaction` now supports optional stateChanges as mentioned below  ([#963](https://github.com/stellar/js-stellar-sdk/pull/963))
+- If `Before` is omitted, it constitutes a creation, if `After` is omitted, it constitutes a deletions, note that `Before` and `After` cannot be be omitted at the same time.
 
 
+```
+/** State Difference information */
+ stateChanges?: LedgerEntryChange[];
+
+interface LedgerEntryChange{
+    type: number;
+    key: xdr.LedgerKey;
+    before: xdr.LedgerEntry | null;
+    after: xdr.LedgerEntry | null;
+  }
+
+```
+
 ## [v12.0.0-rc.3](https://github.com/stellar/js-stellar-sdk/compare/v11.3.0...v12.0.0-rc.3)
 
 ### Breaking Changes
diff --git a/src/rpc/api.ts b/src/rpc/api.ts
index cbfb8e442..0ec813c08 100644
--- a/src/rpc/api.ts
+++ b/src/rpc/api.ts
@@ -168,7 +168,7 @@ export namespace Api {
     value: string;
   }
 
-  export interface RawLedgerEntryChange {
+  interface RawLedgerEntryChange {
     type: number;
     /** This is LedgerKey in base64 */
     key: string;
diff --git a/test/unit/server/soroban/simulate_transaction_test.js b/test/unit/server/soroban/simulate_transaction_test.js
index 55de24a89..863ad6b13 100644
--- a/test/unit/server/soroban/simulate_transaction_test.js
+++ b/test/unit/server/soroban/simulate_transaction_test.js
@@ -18,6 +18,14 @@ describe("Server#simulateTransaction", async function (done) {
   let contract = new StellarSdk.Contract(contractId);
   let address = contract.address().toScAddress();
 
+  const accountId =
+      "GBZXN7PIRZGNMHGA7MUUUF4GWPY5AYPV6LY4UV2GL6VJGIQRXFDNMADI";
+  const accountKey = xdr.LedgerKey.account(
+      new xdr.LedgerKeyAccount({
+        accountId: Keypair.fromPublicKey(accountId).xdrPublicKey(),
+      }),
+  );
+
   const simulationResponse = await invokeSimulationResponse(address);
   const parsedSimulationResponse = {
     id: simulationResponse.id,
@@ -35,7 +43,7 @@ describe("Server#simulateTransaction", async function (done) {
     stateChanges: [
       {
         type: 2,
-        key: "example-key-2",
+        key: accountKey,
         before: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
           data: new xdr.LedgerEntryData(),
@@ -189,7 +197,7 @@ describe("Server#simulateTransaction", async function (done) {
           expected.stateChanges = [
             {
               type: 2,
-              key: "example-key-2",
+              key: accountKey,
               before: new xdr.LedgerEntry({
                 lastModifiedLedgerSeq: 0,
                 data: new xdr.LedgerEntryData(),
@@ -203,7 +211,7 @@ describe("Server#simulateTransaction", async function (done) {
             },
             {
               type: 1,
-              key: "example-key-1",
+              key: accountKey,
               before: null,
               after: new xdr.LedgerEntry({
                 lastModifiedLedgerSeq: 0,
@@ -213,7 +221,7 @@ describe("Server#simulateTransaction", async function (done) {
             },
             {
               type: 3,
-              key: "example-key-3",
+              key: accountKey,
               before: new xdr.LedgerEntry({
                 lastModifiedLedgerSeq: 0,
                 data: new xdr.LedgerEntryData(),
@@ -316,6 +324,8 @@ function simulationResponseError(events) {
 }
 
 function baseSimulationResponse(results) {
+  const accountId = "GBZXN7PIRZGNMHGA7MUUUF4GWPY5AYPV6LY4UV2GL6VJGIQRXFDNMADI";
+
   return {
     id: 1,
     events: [],
@@ -330,7 +340,11 @@ function baseSimulationResponse(results) {
     stateChanges: [
       {
         type: 2,
-        key: "example-key-2",
+        key: xdr.LedgerKey.account(
+            new xdr.LedgerKeyAccount({
+              accountId: Keypair.fromPublicKey(accountId).xdrPublicKey(),
+            }),
+        ).toXDR("base64"),
         before: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
           data: new xdr.LedgerEntryData(),
@@ -357,12 +371,19 @@ async function invokeSimulationResponseWithRestoration(address) {
 }
 
 async function invokeSimulationResponseWithStateChanges(address) {
+  const accountId = "GBZXN7PIRZGNMHGA7MUUUF4GWPY5AYPV6LY4UV2GL6VJGIQRXFDNMADI";
+
   return {
+
     ...(await invokeSimulationResponse(address)),
     stateChanges: [
       {
         type: 2,
-        key: "example-key-2",
+        key: xdr.LedgerKey.account(
+            new xdr.LedgerKeyAccount({
+              accountId: Keypair.fromPublicKey(accountId).xdrPublicKey(),
+            }),
+        ).toXDR("base64"),
         before: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
           data: new xdr.LedgerEntryData(),
@@ -376,7 +397,11 @@ async function invokeSimulationResponseWithStateChanges(address) {
       },
       {
         type: 1,
-        key: "example-key-1",
+        key: xdr.LedgerKey.account(
+            new xdr.LedgerKeyAccount({
+              accountId: Keypair.fromPublicKey(accountId).xdrPublicKey(),
+            }),
+        ).toXDR("base64"),
         before: null,
         after: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
@@ -386,7 +411,11 @@ async function invokeSimulationResponseWithStateChanges(address) {
       },
       {
         type: 3,
-        key: "example-key-3",
+        key: xdr.LedgerKey.account(
+            new xdr.LedgerKeyAccount({
+              accountId: Keypair.fromPublicKey(accountId).xdrPublicKey(),
+            }),
+        ).toXDR("base64"),
         before: new xdr.LedgerEntry({
           lastModifiedLedgerSeq: 0,
           data: new xdr.LedgerEntryData(),

From c577557838131033201c01aa8354c61583fccccb Mon Sep 17 00:00:00 2001
From: Prit Sheth <prit.sheth@stellar.org>
Date: Thu, 30 May 2024 14:57:04 -0700
Subject: [PATCH 10/10] Use spread operator

---
 src/rpc/api.ts     |  2 +-
 src/rpc/parsers.ts | 21 +++++++++++----------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/rpc/api.ts b/src/rpc/api.ts
index 0ec813c08..25591b379 100644
--- a/src/rpc/api.ts
+++ b/src/rpc/api.ts
@@ -178,7 +178,7 @@ export namespace Api {
     after: string | null;
   }
 
-  export interface LedgerEntryChange{
+  export interface LedgerEntryChange {
     type: number;
     key: xdr.LedgerKey;
     before: xdr.LedgerEntry | null;
diff --git a/src/rpc/parsers.ts b/src/rpc/parsers.ts
index 16be6fa71..a54a83434 100644
--- a/src/rpc/parsers.ts
+++ b/src/rpc/parsers.ts
@@ -141,16 +141,17 @@ function parseSuccessful(
       })[0]
     }),
 
-    stateChanges: sim.stateChanges?.length ?? 0 > 0
-        ? sim.stateChanges?.map((entryChange) => {
-          return {
-            type: entryChange.type,
-            key: xdr.LedgerKey.fromXDR(entryChange.key, 'base64'),
-            before: entryChange.before ? xdr.LedgerEntry.fromXDR(entryChange.before, 'base64') : null,
-            after: entryChange.after ? xdr.LedgerEntry.fromXDR(entryChange.after, 'base64') : null,
-          };
-        })
-        : undefined,
+    ...(sim.stateChanges?.length ?? 0 > 0) && {
+      stateChanges: sim.stateChanges?.map((entryChange) => {
+        return {
+          type: entryChange.type,
+          key: xdr.LedgerKey.fromXDR(entryChange.key, 'base64'),
+          before: entryChange.before ? xdr.LedgerEntry.fromXDR(entryChange.before, 'base64') : null,
+          after: entryChange.after ? xdr.LedgerEntry.fromXDR(entryChange.after, 'base64') : null,
+        };
+      })
+    }
+
   };
 
   if (!sim.restorePreamble || sim.restorePreamble.transactionData === '') {