Reduced a memory allocation by using collection expressions

Author: Taritsyn

samples/JavaScriptEngineSwitcher.Sample.Logic/Services/FileContentService.cs

@@ -88,7 +88,7 @@ private string GetPhysicalFilePath(string filePath)
 #endif
 			string physicalFilePath = Path.Combine(
 				applicationDirectoryPath,
-				filePath.Replace('/', '\\').TrimStart(new char[] { '\\' })
+				filePath.Replace('/', '\\').TrimStart(['\\'])
 			);
 
 			return physicalFilePath;

src/JavaScriptEngineSwitcher.ChakraCore/ChakraCoreJsEngine.cs

@@ -427,14 +427,11 @@ private WrapperException WrapJsException(OriginalException originalException,
 							string messageWithTypeAndCallStack = stackPropertyValue.ValueType == JsValueType.String ?
 								stackPropertyValue.ToString() : string.Empty;
 							string messageWithType = errorValue.ConvertToString().ToString();
-							string rawCallStack = messageWithTypeAndCallStack
-								.TrimStart(messageWithType)
-								.TrimStart("Error")
-								.TrimStart(new char[] { '\n', '\r' })
-								;
+							string rawCallStack = CoreErrorHelpers.GetErrorLocationFromMessage(
+								messageWithTypeAndCallStack, messageWithType);
 							string callStackWithSourceFragment = string.Empty;
-
 							ErrorLocationItem[] callStackItems = CoreErrorHelpers.ParseErrorLocation(rawCallStack);
+
 							if (callStackItems.Length > 0)
 							{
 								ErrorLocationItem firstCallStackItem = callStackItems[0];

src/JavaScriptEngineSwitcher.ChakraCore/Helpers/ReflectionHelpers.cs

@@ -20,16 +20,16 @@ namespace JavaScriptEngineSwitcher.ChakraCore.Helpers
 	internal static class ReflectionHelpers
 	{
 		private static readonly PropertyInfo[] _disallowedProperties =
-		{
+		[
 			typeof(Delegate).GetProperty("Method"),
 			typeof(Exception).GetProperty("TargetSite")
-		};
+		];
 
 		private static readonly MethodInfo[] _disallowedMethods =
-		{
+		[
 			typeof(object).GetMethod("GetType"),
 			typeof(Exception).GetMethod("GetType")
-		};
+		];
 
 
 		public static BindingFlags GetDefaultBindingFlags(bool instance)
@@ -187,9 +187,8 @@ public static MethodBase GetBestFitMethod(MethodBase[] methods, object[] argValu
 
 			try
 			{
-				for (int methodIndex = 0; methodIndex < methodCount; methodIndex++)
+				foreach (MethodBase method in methods)
 				{
-					MethodBase method = methods[methodIndex];
 					ParameterInfo[] parameters = method.GetParameters();
 					ushort compatibilityScore;
 

src/JavaScriptEngineSwitcher.ChakraCore/JavaScriptEngineSwitcher.ChakraCore.csproj

@@ -27,7 +27,8 @@
     <PackageReleaseNotes>1. The value of a read-only field in an embedded object or type can no longer be changed;
 2. Performed a migration to the modern C# null/not-null checks;
 3. Added support for .NET 10;
-4. In the `lock` statements for .NET 10 target now uses a instances of the `System.Threading.Lock` class.</PackageReleaseNotes>
+4. In the `lock` statements for .NET 10 target now uses a instances of the `System.Threading.Lock` class;
+5. Reduced a memory allocation by using collection expressions.</PackageReleaseNotes>
   </PropertyGroup>
 
   <ItemGroup>

src/JavaScriptEngineSwitcher.ChakraCore/JsRt/JsValue.cs

@@ -263,7 +263,7 @@ public byte[] ArrayBufferBytes
 
 				if (bufferLength == 0)
 				{
-					return new byte[0];
+					return [];
 				}
 
 				var buffer = new byte[bufferLength];

src/JavaScriptEngineSwitcher.ChakraCore/JsRt/TypeMapper.cs

@@ -330,8 +330,7 @@ private EmbeddedObject CreateEmbeddedFunction(Delegate del)
 			JsValue functionValue = JsValue.CreateFunction(nativeFunction);
 			SetNonEnumerableProperty(functionValue, ExternalObjectPropertyName, objValue);
 
-			var embeddedObject = new EmbeddedObject(del, functionValue,
-				new List<JsNativeFunction> { nativeFunction });
+			var embeddedObject = new EmbeddedObject(del, functionValue, [nativeFunction]);
 
 			return embeddedObject;
 		}
@@ -642,7 +641,7 @@ private void ProjectProperties(EmbeddedItem externalItem)
 
 						try
 						{
-							result = property.GetValue(obj, new object[0]);
+							result = property.GetValue(obj, []);
 						}
 						catch (Exception e)
 						{
@@ -698,7 +697,7 @@ private void ProjectProperties(EmbeddedItem externalItem)
 
 						try
 						{
-							property.SetValue(obj, value, new object[0]);
+							property.SetValue(obj, value, []);
 						}
 						catch (Exception e)
 						{
@@ -842,7 +841,7 @@ private Dictionary<string, List<MethodInfo>> GetAvailableMethodGroups(MethodInfo
 			int methodCount = methods.Length;
 			if (methodCount == 0)
 			{
-				return new Dictionary<string, List<MethodInfo>>();
+				return [];
 			}
 
 			var availableMethodGroups = new Dictionary<string, List<MethodInfo>>(methodCount);
@@ -864,7 +863,7 @@ private Dictionary<string, List<MethodInfo>> GetAvailableMethodGroups(MethodInfo
 				}
 				else
 				{
-					methodGroup = new List<MethodInfo> { method };
+					methodGroup = [method];
 					availableMethodGroups.Add(methodName, methodGroup);
 				}
 			}
@@ -899,7 +898,7 @@ private object[] GetHostItemMemberArguments(JsValue[] args, int maxArgCount = -1
 			}
 			else
 			{
-				processedArgs = new object[0];
+				processedArgs = [];
 			}
 
 			return processedArgs;

src/JavaScriptEngineSwitcher.ChakraCore/readme.txt

@@ -36,7 +36,8 @@
    2. Performed a migration to the modern C# null/not-null checks;
    3. Added support for .NET 10;
    4. In the `lock` statements for .NET 10 target now uses a instances of the
-      `System.Threading.Lock` class.
+      `System.Threading.Lock` class;
+   5. Reduced a memory allocation by using collection expressions.
 
    =============
    DOCUMENTATION

src/JavaScriptEngineSwitcher.Core/Extensions/StringExtensions.cs

@@ -7,6 +7,12 @@ namespace JavaScriptEngineSwitcher.Core.Extensions
 	/// </summary>
 	public static class StringExtensions
 	{
+		/// <summary>
+		/// Array of strings used to find the newline
+		/// </summary>
+		private static readonly string[] _newLineStrings = ["\r\n", "\r", "\n"];
+
+
 		/// <summary>
 		/// Returns a value indicating whether the specified quoted string occurs within this string
 		/// </summary>
@@ -68,14 +74,35 @@ public static string TrimStart(this string source, string trimString)
 		/// </summary>
 		/// <param name="source">Instance of <see cref="String"/></param>
 		/// <returns>An array of lines</returns>
+		[Obsolete]
 		public static string[] SplitToLines(this string source)
 		{
 			if (source is null)
 			{
 				throw new ArgumentNullException(nameof(source));
 			}
 
-			string[] result = source.Split(new[] { "\r\n", "\r", "\n" }, StringSplitOptions.None);
+			string[] result = source.Split(_newLineStrings, StringSplitOptions.None);
+
+			return result;
+		}
+
+		/// <summary>
+		/// Splits a string into lines
+		/// </summary>
+		/// <param name="source">Instance of <see cref="String"/></param>
+		/// <param name="options"><see cref="StringSplitOptions.RemoveEmptyEntries"/> to omit empty array
+		/// elements from the array returned; or <see cref="StringSplitOptions.None"/> to include empty
+		/// array elements in the array returned</param>
+		/// <returns>An array of lines</returns>
+		internal static string[] SplitToLines(this string source, StringSplitOptions options)
+		{
+			if (source is null)
+			{
+				throw new ArgumentNullException(nameof(source));
+			}
+
+			string[] result = source.Split(_newLineStrings, options);
 
 			return result;
 		}

src/JavaScriptEngineSwitcher.Core/Helpers/JsErrorHelpers.cs

@@ -9,6 +9,7 @@
 
 using JavaScriptEngineSwitcher.Core.Extensions;
 using JavaScriptEngineSwitcher.Core.Resources;
+using JavaScriptEngineSwitcher.Core.Utilities;
 
 namespace JavaScriptEngineSwitcher.Core.Helpers
 {
@@ -39,53 +40,107 @@ public static class JsErrorHelpers
 				@")" +
 				@"(?: -> (?<sourceFragment>[^\n\r]+))?$");
 
+
+		/// <summary>
+		/// Gets a string representation of the script error location
+		/// </summary>
+		/// <param name="message">Error message with the script error location</param>
+		/// <param name="messageWithoutErrorLocation">Error message without the script error location</param>
+		/// <returns>String representation of the script error location</returns>
+		public static string GetErrorLocationFromMessage(string message, string messageWithoutErrorLocation)
+		{
+			if (string.IsNullOrWhiteSpace(message))
+			{
+				return string.Empty;
+			}
+
+			if (string.IsNullOrWhiteSpace(messageWithoutErrorLocation))
+			{
+				return message;
+			}
+
+			string errorLocation = message
+				.TrimStart(messageWithoutErrorLocation)
+				.TrimStart(EnvironmentShortcuts.NewLineChars)
+				;
+
+			return errorLocation;
+		}
+
 		/// <summary>
 		/// Parses a string representation of the script error location to produce an array of
 		/// <see cref="ErrorLocationItem"/> instances
 		/// </summary>
 		/// <param name="errorLocation">String representation of the script error location</param>
 		/// <returns>An array of <see cref="ErrorLocationItem"/> instances</returns>
 		public static ErrorLocationItem[] ParseErrorLocation(string errorLocation)
+		{
+			return ParseErrorLocation(errorLocation, MapErrorLocationItem);
+		}
+
+		/// <summary>
+		/// Parses a string representation of the script error location to produce an array of
+		/// <see cref="ErrorLocationItem"/> instances
+		/// </summary>
+		/// <param name="errorLocation">String representation of the script error location</param>
+		/// <param name="itemMapper">Error location item mapper</param>
+		/// <returns>An array of <see cref="ErrorLocationItem"/> instances</returns>
+		public static ErrorLocationItem[] ParseErrorLocation(string errorLocation,
+			Func<string, ErrorLocationItem> itemMapper)
 		{
 			if (string.IsNullOrWhiteSpace(errorLocation))
 			{
-				return new ErrorLocationItem[0];
+				return [];
 			}
 
-			var errorLocationItems = new List<ErrorLocationItem>();
-			string[] lines = errorLocation.SplitToLines();
+			if (itemMapper is null)
+			{
+				throw new ArgumentNullException(nameof(itemMapper));
+			}
+
+			string[] lines = errorLocation.SplitToLines(StringSplitOptions.RemoveEmptyEntries);
 			int lineCount = lines.Length;
+			var errorLocationItems = new List<ErrorLocationItem>(lineCount);
 
-			for (int lineIndex = 0; lineIndex < lineCount; lineIndex++)
+			foreach (string line in lines)
 			{
-				string line = lines[lineIndex];
-				Match lineMatch = _errorLocationLineRegex.Match(line);
-
-				if (lineMatch.Success)
+				ErrorLocationItem errorLocationItem = itemMapper(line);
+				if (errorLocationItem is not null)
 				{
-					GroupCollection lineGroups = lineMatch.Groups;
-
-					var errorLocationItem = new ErrorLocationItem
-					{
-						FunctionName = lineGroups["functionName"].Value,
-						DocumentName = lineGroups["documentName"].Value,
-						LineNumber = int.Parse(lineGroups["lineNumber"].Value),
-						ColumnNumber = lineGroups["columnNumber"].Success ?
-							int.Parse(lineGroups["columnNumber"].Value) : 0,
-						SourceFragment = lineGroups["sourceFragment"].Value
-					};
 					errorLocationItems.Add(errorLocationItem);
 				}
 				else
 				{
 					Debug.WriteLine(string.Format(Strings.Runtime_InvalidErrorLocationLineFormat, line));
-					return new ErrorLocationItem[0];
+					return [];
 				}
 			}
 
 			return errorLocationItems.ToArray();
 		}
 
+		private static ErrorLocationItem MapErrorLocationItem(string errorLocationLine)
+		{
+			ErrorLocationItem item = null;
+			Match lineMatch = _errorLocationLineRegex.Match(errorLocationLine);
+
+			if (lineMatch.Success)
+			{
+				GroupCollection lineGroups = lineMatch.Groups;
+				item = new ErrorLocationItem
+				{
+					FunctionName = lineGroups["functionName"].Value,
+					DocumentName = lineGroups["documentName"].Value,
+					LineNumber = int.Parse(lineGroups["lineNumber"].Value),
+					ColumnNumber = lineGroups["columnNumber"].Success ?
+						int.Parse(lineGroups["columnNumber"].Value) : 0,
+					SourceFragment = lineGroups["sourceFragment"].Value
+				};
+			}
+
+			return item;
+		}
+
 		/// <summary>
 		/// Produces a string representation of the script error location from array of
 		/// <see cref="ErrorLocationItem"/> instances

src/JavaScriptEngineSwitcher.Core/Helpers/TextHelpers.cs

@@ -4,6 +4,7 @@
 using AdvancedStringBuilder;
 
 using JavaScriptEngineSwitcher.Core.Extensions;
+using JavaScriptEngineSwitcher.Core.Utilities;
 
 namespace JavaScriptEngineSwitcher.Core.Helpers
 {
@@ -15,7 +16,7 @@ public static class TextHelpers
 		/// <summary>
 		/// Array of characters used to find the next line break
 		/// </summary>
-		private static readonly char[] _nextLineBreakChars = new char[] { '\r', '\n' };
+		private static readonly char[] _nextLineBreakChars = EnvironmentShortcuts.NewLineChars;
 
 
 		/// <summary>