In configuration settings of the V8 JS engine was added one new property - HeapExpansionMultiplier (default 0)

Author: Taritsyn

src/JavaScriptEngineSwitcher.V8/JavaScriptEngineSwitcher.V8.csproj

@@ -31,7 +31,8 @@ This package does not contain the native ClearScript.V8 assemblies. Therefore, y
     <PackageIconFullPath>../../Icons/JavaScriptEngineSwitcher_V8_Logo128x128.png</PackageIconFullPath>
     <PackageReleaseNotes>1. Microsoft ClearScript.V8 was updated to version 7.1.1;
 2. Added support of .NET Standard 2.1;
-3. Added support of Linux (ARM).</PackageReleaseNotes>
+3. Added support of Linux (ARM);
+4. In configuration settings of the V8 JS engine was added one new property - `HeapExpansionMultiplier` (default `0`).</PackageReleaseNotes>
   </PropertyGroup>
 
   <ItemGroup>

src/JavaScriptEngineSwitcher.V8/V8JsEngine.cs

@@ -99,6 +99,7 @@ public V8JsEngine(V8Settings settings)
 
 			var constraints = new OriginalRuntimeConstraints
 			{
+				HeapExpansionMultiplier = v8Settings.HeapExpansionMultiplier,
 				MaxNewSpaceSize = v8Settings.MaxNewSpaceSize,
 				MaxOldSpaceSize = v8Settings.MaxOldSpaceSize,
 			};

src/JavaScriptEngineSwitcher.V8/V8Settings.cs

@@ -57,6 +57,26 @@ public bool DisableGlobalMembers
 			set;
 		}
 
+		/// <summary>
+		/// Gets or sets a heap expansion multiplier
+		/// </summary>
+		/// <remarks>
+		/// <para>
+		/// When set to a value greater than 1, this property enables on-demand heap expansion,
+		/// which automatically increases the maximum heap size by the specified multiplier
+		/// whenever the script engine is close to exceeding the current limit. Note that a buggy
+		/// or malicious script can still cause an application to fail by exhausting its address
+		/// space or total available memory. On-demand heap expansion is recommended for use in
+		/// conjunction with heap size monitoring (see <see cref="MaxHeapSize"/> property to help
+		/// contain runaway scripts.
+		/// </para>
+		/// </remarks>
+		public double HeapExpansionMultiplier
+		{
+			get;
+			set;
+		}
+
 		/// <summary>
 		/// Gets or sets a minimum time interval between consecutive heap size samples
 		/// </summary>
@@ -159,6 +179,7 @@ public V8Settings()
 			EnableRemoteDebugging = false;
 			DebugPort = 9222;
 			DisableGlobalMembers = false;
+			HeapExpansionMultiplier = 0;
 			HeapSizeSampleInterval = TimeSpan.Zero;
 			MaxHeapSize = UIntPtr.Zero;
 			MaxNewSpaceSize = 0;

src/JavaScriptEngineSwitcher.V8/readme.txt

@@ -32,7 +32,9 @@
    =============
    1. Microsoft ClearScript.V8 was updated to version 7.1.1;
    2. Added support of .NET Standard 2.1;
-   3. Added support of Linux (ARM).
+   3. Added support of Linux (ARM);
+   4. In configuration settings of the V8 JS engine was added one new property -
+      `HeapExpansionMultiplier` (default `0`).
 
    =============
    DOCUMENTATION