diff --git a/ReactCommon/hermes/inspector/tools/msggen/__tests__/CommandTest.js b/ReactCommon/hermes/inspector/tools/msggen/__tests__/CommandTest.js
index c4855515605a25..dd08a012c4bf57 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/__tests__/CommandTest.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/__tests__/CommandTest.js
@@ -8,11 +8,11 @@ import { Command } from '../src/Command.js';
 
 test('parses simple command', () => {
   let obj = {
-    "name": "setBreakpointsActive",
-    "parameters": [
-      { "name": "active", "type": "boolean", "description": "New value for breakpoints active state." }
+    'name': 'setBreakpointsActive',
+    'parameters': [
+      { 'name': 'active', 'type': 'boolean', 'description': 'New value for breakpoints active state.' },
     ],
-    "description": "Activates / deactivates all breakpoints on the page."
+    'description': 'Activates / deactivates all breakpoints on the page.',
   };
   let command = Command.create('Debugger', obj, false);
 
@@ -31,16 +31,16 @@ test('parses simple command', () => {
 
 test('parses command with return', () => {
   let obj = {
-    "name": "setBreakpoint",
-    "parameters": [
-      { "name": "location", "$ref": "Location", "description": "Location to set breakpoint in." },
-      { "name": "condition", "type": "string", "optional": true, "description": "Expression to use as a breakpoint condition. When specified, debugger will only stop on the breakpoint if this expression evaluates to true." }
+    'name': 'setBreakpoint',
+    'parameters': [
+      { 'name': 'location', '$ref': 'Location', 'description': 'Location to set breakpoint in.' },
+      { 'name': 'condition', 'type': 'string', 'optional': true, 'description': 'Expression to use as a breakpoint condition. When specified, debugger will only stop on the breakpoint if this expression evaluates to true.' },
     ],
-    "returns": [
-      { "name": "breakpointId", "$ref": "BreakpointId", "description": "Id of the created breakpoint for further reference." },
-      { "name": "actualLocation", "$ref": "Location", "description": "Location this breakpoint resolved into." }
+    'returns': [
+      { 'name': 'breakpointId', '$ref': 'BreakpointId', 'description': 'Id of the created breakpoint for further reference.' },
+      { 'name': 'actualLocation', '$ref': 'Location', 'description': 'Location this breakpoint resolved into.' },
     ],
-    "description": "Sets JavaScript breakpoint at a given location."
+    'description': 'Sets JavaScript breakpoint at a given location.',
   };
   let command = Command.create('Debugger', obj, false);
 
diff --git a/ReactCommon/hermes/inspector/tools/msggen/__tests__/EventTest.js b/ReactCommon/hermes/inspector/tools/msggen/__tests__/EventTest.js
index 8028e1054ae5e1..5ef40d749c5c52 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/__tests__/EventTest.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/__tests__/EventTest.js
@@ -8,8 +8,8 @@ import { Event } from '../src/Event.js';
 
 test('parses simple event', () => {
   let obj = {
-    "name": "resumed",
-    "description": "Fired when the virtual machine resumed execution."
+    'name': 'resumed',
+    'description': 'Fired when the virtual machine resumed execution.',
   };
   let event = Event.create('Debugger', obj, false);
 
@@ -25,12 +25,12 @@ test('parses simple event', () => {
 
 test('parses event with params', () => {
   let obj = {
-    "name": "breakpointResolved",
-    "parameters": [
-      { "name": "breakpointId", "$ref": "BreakpointId", "description": "Breakpoint unique identifier." },
-      { "name": "location", "$ref": "Location", "description": "Actual breakpoint location." }
+    'name': 'breakpointResolved',
+    'parameters': [
+      { 'name': 'breakpointId', '$ref': 'BreakpointId', 'description': 'Breakpoint unique identifier.' },
+      { 'name': 'location', '$ref': 'Location', 'description': 'Actual breakpoint location.' },
     ],
-    "description": "Fired when breakpoint is resolved to an actual script and location."
+    'description': 'Fired when breakpoint is resolved to an actual script and location.',
   };
   let event = Event.create('Debugger', obj, false);
 
diff --git a/ReactCommon/hermes/inspector/tools/msggen/__tests__/HeaderWriterTest.js b/ReactCommon/hermes/inspector/tools/msggen/__tests__/HeaderWriterTest.js
index b04b6ffcee5255..d77742d54a481e 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/__tests__/HeaderWriterTest.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/__tests__/HeaderWriterTest.js
@@ -23,14 +23,14 @@ beforeEach(() => {
 
 test('emits type decl', () => {
   let obj = {
-    "id": "Location",
-    "type": "object",
-    "properties": [
-        { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Script identifier as reported in the <code>Debugger.scriptParsed</code>." },
-        { "name": "lineNumber", "type": "integer", "description": "Line number in the script (0-based)." },
-        { "name": "columnNumber", "type": "integer", "optional": true, "description": "Column number in the script (0-based)." }
+    'id': 'Location',
+    'type': 'object',
+    'properties': [
+        { 'name': 'scriptId', '$ref': 'Runtime.ScriptId', 'description': 'Script identifier as reported in the <code>Debugger.scriptParsed</code>.' },
+        { 'name': 'lineNumber', 'type': 'integer', 'description': 'Line number in the script (0-based).' },
+        { 'name': 'columnNumber', 'type': 'integer', 'optional': true, 'description': 'Column number in the script (0-based).' },
     ],
-    "description": "Location in the source code."
+    'description': 'Location in the source code.',
   };
   let type = Type.create('Debugger', obj);
 
@@ -51,14 +51,14 @@ test('emits type decl', () => {
 
 test('emits request decl', () => {
   let obj = {
-    "name": "getScriptSource",
-    "parameters": [
-      { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Id of the script to get source for." }
+    'name': 'getScriptSource',
+    'parameters': [
+      { 'name': 'scriptId', '$ref': 'Runtime.ScriptId', 'description': 'Id of the script to get source for.' },
     ],
-    "returns": [
-      { "name": "scriptSource", "type": "string", "description": "Script source." }
+    'returns': [
+      { 'name': 'scriptSource', 'type': 'string', 'description': 'Script source.' },
     ],
-    "description": "Returns source for the script with given id."
+    'description': 'Returns source for the script with given id.',
   };
   let command = Command.create('Debugger', obj);
 
@@ -79,14 +79,14 @@ test('emits request decl', () => {
 
 test('emits response decl', () => {
   let obj = {
-    "name": "getScriptSource",
-    "parameters": [
-      { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Id of the script to get source for." }
+    'name': 'getScriptSource',
+    'parameters': [
+      { 'name': 'scriptId', '$ref': 'Runtime.ScriptId', 'description': 'Id of the script to get source for.' },
     ],
-    "returns": [
-      { "name": "scriptSource", "type": "string", "description": "Script source." }
+    'returns': [
+      { 'name': 'scriptSource', 'type': 'string', 'description': 'Script source.' },
     ],
-    "description": "Returns source for the script with given id."
+    'description': 'Returns source for the script with given id.',
   };
   let command = Command.create('Debugger', obj);
 
@@ -105,11 +105,11 @@ test('emits response decl', () => {
 
 test('emits notification decl', () => {
   let obj = {
-    "name": "messageAdded",
-    "parameters": [
-      { "name": "message", "$ref": "ConsoleMessage", "description": "Console message that has been added." }
+    'name': 'messageAdded',
+    'parameters': [
+      { 'name': 'message', '$ref': 'ConsoleMessage', 'description': 'Console message that has been added.' },
     ],
-    "description": "Issued when new console message is added."
+    'description': 'Issued when new console message is added.',
   };
   let event = Event.create('Console', obj);
 
diff --git a/ReactCommon/hermes/inspector/tools/msggen/__tests__/ImplementationWriterTest.js b/ReactCommon/hermes/inspector/tools/msggen/__tests__/ImplementationWriterTest.js
index 8485cb7fe2fb41..13139401da151e 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/__tests__/ImplementationWriterTest.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/__tests__/ImplementationWriterTest.js
@@ -9,7 +9,7 @@ import {
   emitNotificationDef,
   emitRequestDef,
   emitResponseDef,
-  emitTypeDef
+  emitTypeDef,
 } from '../src/ImplementationWriter';
 import { Event } from '../src/Event';
 import { Command } from '../src/Command';
@@ -23,14 +23,14 @@ beforeEach(() => {
 
 test('emits type def', () => {
   let obj = {
-    "id": "Location",
-    "type": "object",
-    "properties": [
-        { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Script identifier as reported in the <code>Debugger.scriptParsed</code>." },
-        { "name": "lineNumber", "type": "integer", "description": "Line number in the script (0-based)." },
-        { "name": "columnNumber", "type": "integer", "optional": true, "description": "Column number in the script (0-based)." }
+    'id': 'Location',
+    'type': 'object',
+    'properties': [
+        { 'name': 'scriptId', '$ref': 'Runtime.ScriptId', 'description': 'Script identifier as reported in the <code>Debugger.scriptParsed</code>.' },
+        { 'name': 'lineNumber', 'type': 'integer', 'description': 'Line number in the script (0-based).' },
+        { 'name': 'columnNumber', 'type': 'integer', 'optional': true, 'description': 'Column number in the script (0-based).' },
     ],
-    "description": "Location in the source code."
+    'description': 'Location in the source code.',
   };
   let type = Type.create('Debugger', obj);
 
@@ -55,14 +55,14 @@ test('emits type def', () => {
 
 test('emits request def', () => {
   let obj = {
-    "name": "getScriptSource",
-    "parameters": [
-      { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Id of the script to get source for." }
+    'name': 'getScriptSource',
+    'parameters': [
+      { 'name': 'scriptId', '$ref': 'Runtime.ScriptId', 'description': 'Id of the script to get source for.' },
     ],
-    "returns": [
-      { "name": "scriptSource", "type": "string", "description": "Script source." }
+    'returns': [
+      { 'name': 'scriptSource', 'type': 'string', 'description': 'Script source.' },
     ],
-    "description": "Returns source for the script with given id."
+    'description': 'Returns source for the script with given id.',
   };
   let command = Command.create('Debugger', obj);
 
@@ -100,14 +100,14 @@ test('emits request def', () => {
 
 test('emits response def', () => {
   let obj = {
-    "name": "getScriptSource",
-    "parameters": [
-      { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Id of the script to get source for." }
+    'name': 'getScriptSource',
+    'parameters': [
+      { 'name': 'scriptId', '$ref': 'Runtime.ScriptId', 'description': 'Id of the script to get source for.' },
     ],
-    "returns": [
-      { "name": "scriptSource", "type": "string", "description": "Script source." }
+    'returns': [
+      { 'name': 'scriptSource', 'type': 'string', 'description': 'Script source.' },
     ],
-    "description": "Returns source for the script with given id."
+    'description': 'Returns source for the script with given id.',
   };
   let command = Command.create('Debugger', obj);
 
@@ -135,11 +135,11 @@ test('emits response def', () => {
 
 test('emits notification def', () => {
   let obj = {
-    "name": "messageAdded",
-    "parameters": [
-      { "name": "message", "$ref": "ConsoleMessage", "description": "Console message that has been added." }
+    'name': 'messageAdded',
+    'parameters': [
+      { 'name': 'message', '$ref': 'ConsoleMessage', 'description': 'Console message that has been added.' },
     ],
-    "description": "Issued when new console message is added."
+    'description': 'Issued when new console message is added.',
   };
   let event = Event.create('Console', obj);
 
diff --git a/ReactCommon/hermes/inspector/tools/msggen/__tests__/PropertyTest.js b/ReactCommon/hermes/inspector/tools/msggen/__tests__/PropertyTest.js
index 6b4e600324b3cf..3e4d468f1f42f7 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/__tests__/PropertyTest.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/__tests__/PropertyTest.js
@@ -8,9 +8,9 @@ import { Property } from '../src/Property.js';
 
 test('parses required primitive prop', () => {
   let obj = {
-    "name": "lineNumber",
-    "type": "integer",
-    "description": "Line number in the script (0-based)."
+    'name': 'lineNumber',
+    'type': 'integer',
+    'description': 'Line number in the script (0-based).',
   };
   let prop = Property.create('Debugger', obj);
 
@@ -27,10 +27,10 @@ test('parses required primitive prop', () => {
 
 test('parses optional primitive prop', () => {
   let obj = {
-    "name": "samplingInterval",
-    "type": "number",
-    "optional": true,
-    "description": "Average sample interval in bytes."
+    'name': 'samplingInterval',
+    'type': 'number',
+    'optional': true,
+    'description': 'Average sample interval in bytes.',
   };
   let prop = Property.create('HeapProfiler', obj);
 
@@ -47,10 +47,10 @@ test('parses optional primitive prop', () => {
 
 test('parses optional ref prop', () => {
   let obj = {
-    "name": "exceptionDetails",
-    "optional": true,
-    "$ref": "Runtime.ExceptionDetails",
-    "description": "Exception details if any."
+    'name': 'exceptionDetails',
+    'optional': true,
+    '$ref': 'Runtime.ExceptionDetails',
+    'description': 'Exception details if any.',
   };
   let prop = Property.create('Debugger', obj);
 
@@ -67,11 +67,11 @@ test('parses optional ref prop', () => {
 
 test('parses recursive ref prop', () => {
   let obj = {
-    "name": "parent",
-    "$ref": "StackTrace",
-    "optional": true,
-    "recursive": true,
-    "description": "Asynchronous JavaScript stack trace..."
+    'name': 'parent',
+    '$ref': 'StackTrace',
+    'optional': true,
+    'recursive': true,
+    'description': 'Asynchronous JavaScript stack trace...',
   };
   let prop = Property.create('Runtime', obj);
 
@@ -89,11 +89,11 @@ test('parses recursive ref prop', () => {
 
 test('parses optional array items prop', () => {
   let obj = {
-    "name": "hitBreakpoints",
-    "type": "array",
-    "optional": true,
-    "items": { "type": "string" },
-    "description": "Hit breakpoints IDs"
+    'name': 'hitBreakpoints',
+    'type': 'array',
+    'optional': true,
+    'items': { 'type': 'string' },
+    'description': 'Hit breakpoints IDs',
   };
   let prop = Property.create('Debugger', obj);
 
@@ -101,8 +101,8 @@ test('parses optional array items prop', () => {
   expect(prop.name).toBe('hitBreakpoints');
   expect(prop.type).toBe('array');
   expect(prop.optional).toBe(true);
-  expect(prop.items).toEqual({ "type": "string" });
-  expect(prop.description).toBe("Hit breakpoints IDs");
+  expect(prop.items).toEqual({ 'type': 'string' });
+  expect(prop.description).toBe('Hit breakpoints IDs');
 
   expect(prop.getFullCppType()).toBe('folly::Optional<std::vector<std::string>>');
   expect(prop.getCppIdentifier()).toBe('hitBreakpoints');
@@ -111,18 +111,18 @@ test('parses optional array items prop', () => {
 
 test('parses array ref prop', () => {
   let obj = {
-    "name": "domains",
-    "type": "array",
-    "items": { "$ref": "Domain" },
-    "description": "List of supported domains."
+    'name': 'domains',
+    'type': 'array',
+    'items': { '$ref': 'Domain' },
+    'description': 'List of supported domains.',
   };
   let prop = Property.create('Schema', obj);
 
   expect(prop.domain).toBe('Schema');
   expect(prop.name).toBe('domains');
   expect(prop.type).toBe('array');
-  expect(prop.items).toEqual({ $ref: "Domain" });
-  expect(prop.description).toBe("List of supported domains.");
+  expect(prop.items).toEqual({ $ref: 'Domain' });
+  expect(prop.description).toBe('List of supported domains.');
 
   expect(prop.getFullCppType()).toBe('std::vector<schema::Domain>');
   expect(prop.getCppIdentifier()).toBe('domains');
diff --git a/ReactCommon/hermes/inspector/tools/msggen/__tests__/TypeTest.js b/ReactCommon/hermes/inspector/tools/msggen/__tests__/TypeTest.js
index 6e8a16e32e5e61..66a697a0cd4ebd 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/__tests__/TypeTest.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/__tests__/TypeTest.js
@@ -8,9 +8,9 @@ import { Type } from '../src/Type.js';
 
 test('parses primitive type', () => {
   let obj = {
-    "id": "Timestamp",
-    "type": "number",
-    "description": "Number of milliseconds since epoch."
+    'id': 'Timestamp',
+    'type': 'number',
+    'description': 'Number of milliseconds since epoch.',
   };
   let type = Type.create('Runtime', obj, false);
 
@@ -26,14 +26,14 @@ test('parses primitive type', () => {
 
 test('parses object type', () => {
   let obj = {
-    "id": "Location",
-    "type": "object",
-    "properties": [
-        { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Script identifier as reported in the <code>Debugger.scriptParsed</code>." },
-        { "name": "lineNumber", "type": "integer", "description": "Line number in the script (0-based)." },
-        { "name": "columnNumber", "type": "integer", "optional": true, "description": "Column number in the script (0-based)." }
+    'id': 'Location',
+    'type': 'object',
+    'properties': [
+        { 'name': 'scriptId', '$ref': 'Runtime.ScriptId', 'description': 'Script identifier as reported in the <code>Debugger.scriptParsed</code>.' },
+        { 'name': 'lineNumber', 'type': 'integer', 'description': 'Line number in the script (0-based).' },
+        { 'name': 'columnNumber', 'type': 'integer', 'optional': true, 'description': 'Column number in the script (0-based).' },
     ],
-    "description": "Location in the source code."
+    'description': 'Location in the source code.',
   };
   let type = Type.create('Debugger', obj, false);
 
diff --git a/ReactCommon/hermes/inspector/tools/msggen/src/ImplementationWriter.js b/ReactCommon/hermes/inspector/tools/msggen/src/ImplementationWriter.js
index 74ca424c1e8839..3f0497eaa90ebb 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/src/ImplementationWriter.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/src/ImplementationWriter.js
@@ -265,7 +265,7 @@ export function emitRequestDef(stream: Writable, command: Command) {
     assign(method, obj, "method");\n\n`);
 
   if (props.length > 0) {
-    stream.write(`dynamic params = obj.at("params");\n`);
+    stream.write('dynamic params = obj.at("params");\n');
 
     for (const prop of props) {
       const id = prop.getCppIdentifier();
@@ -280,7 +280,7 @@ export function emitRequestDef(stream: Writable, command: Command) {
   stream.write(`dynamic ${cppNs}::${cppType}::toDynamic() const {\n`);
 
   if (props.length > 0) {
-    stream.write(`dynamic params = dynamic::object;\n`);
+    stream.write('dynamic params = dynamic::object;\n');
 
     for (const prop of props) {
       const id = prop.getCppIdentifier();
@@ -296,7 +296,7 @@ export function emitRequestDef(stream: Writable, command: Command) {
   `);
 
   if (props.length > 0) {
-    stream.write(`put(obj, "params", std::move(params));\n`);
+    stream.write('put(obj, "params", std::move(params));\n');
   }
 
   stream.write(`return obj;
@@ -321,7 +321,7 @@ export function emitResponseDef(stream: Writable, command: Command) {
 
   const props = command.returns || [];
   if (props.length > 0) {
-    stream.write(`dynamic res = obj.at("result");\n`);
+    stream.write('dynamic res = obj.at("result");\n');
 
     for (const prop of props) {
       const id = prop.getCppIdentifier();
@@ -336,7 +336,7 @@ export function emitResponseDef(stream: Writable, command: Command) {
   stream.write(`dynamic ${cppNs}::${cppType}::toDynamic() const {\n`);
 
   if (props.length > 0) {
-    stream.write(`dynamic res = dynamic::object;\n`);
+    stream.write('dynamic res = dynamic::object;\n');
 
     for (const prop of props) {
       const id = prop.getCppIdentifier();
@@ -369,7 +369,7 @@ export function emitNotificationDef(stream: Writable, event: Event) {
     assign(method, obj, "method");\n\n`);
 
   if (props.length > 0) {
-    stream.write(`dynamic params = obj.at("params");\n`);
+    stream.write('dynamic params = obj.at("params");\n');
 
     for (const prop of props) {
       const id = prop.getCppIdentifier();
@@ -384,7 +384,7 @@ export function emitNotificationDef(stream: Writable, event: Event) {
   stream.write(`dynamic ${cppNs}::${cppType}::toDynamic() const {\n`);
 
   if (props.length > 0) {
-    stream.write(`dynamic params = dynamic::object;\n`);
+    stream.write('dynamic params = dynamic::object;\n');
 
     for (const prop of props) {
       const id = prop.getCppIdentifier();
@@ -399,7 +399,7 @@ export function emitNotificationDef(stream: Writable, event: Event) {
   `);
 
   if (props.length > 0) {
-    stream.write(`put(obj, "params", std::move(params));\n`);
+    stream.write('put(obj, "params", std::move(params));\n');
   }
 
   stream.write(`return obj;
diff --git a/ReactCommon/hermes/inspector/tools/msggen/src/TestHelpers.js b/ReactCommon/hermes/inspector/tools/msggen/src/TestHelpers.js
index 1f7bc6ee961c1c..b54300d53fd5ef 100644
--- a/ReactCommon/hermes/inspector/tools/msggen/src/TestHelpers.js
+++ b/ReactCommon/hermes/inspector/tools/msggen/src/TestHelpers.js
@@ -1,6 +1,8 @@
 /**
  * Copyright 2004-present Facebook. All Rights Reserved.
  */
+ /*global expect*/
+
 'use strict';
 
 // munges string so that it's nice to look at in a test diff