Fixed a error #59 “Unhandled exception when JS exception is thrown”

Author: Taritsyn

Diff for: src/JavaScriptEngineSwitcher.Core/Helpers/JsErrorHelpers.cs

@@ -604,7 +604,14 @@ private static string GetSourceFragment(string source, int position, int length,
 
 				var leftOffset = (int)Math.Floor((double)maxFragmentLength / 2);
 				int fragmentStartPosition = columnNumber - leftOffset - 1;
-				if (fragmentStartPosition < position)
+				if (fragmentStartPosition > position)
+				{
+					if (length - fragmentStartPosition < maxFragmentLength)
+					{
+						fragmentStartPosition = length - maxFragmentLength;
+					}
+				}
+				else
 				{
 					fragmentStartPosition = position;
 				}
@@ -613,12 +620,10 @@ private static string GetSourceFragment(string source, int position, int length,
 				if (fragmentStartPosition > position)
 				{
 					startPart = ellipsisSymbol;
-					fragmentLength--;
 				}
-				if (fragmentStartPosition + maxFragmentLength < length)
+				if (fragmentStartPosition + fragmentLength < length)
 				{
 					endPart = ellipsisSymbol;
-					fragmentLength--;
 				}
 
 				StringBuilder fragmentBuilder = StringBuilderPool.GetBuilder();

Diff for: src/JavaScriptEngineSwitcher.Core/JavaScriptEngineSwitcher.Core.csproj

@@ -3,7 +3,7 @@
 	<PropertyGroup>
 		<Product>JS Engine Switcher: Core</Product>
 		<VersionPrefix>3.0.0</VersionPrefix>
-		<VersionSuffix>beta4</VersionSuffix>
+		<VersionSuffix>beta9</VersionSuffix>
 		<TargetFrameworks>net40-client;net45;net471;netstandard1.3;netstandard2.0</TargetFrameworks>
 		<NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.3' ">1.6.0</NetStandardImplicitPackageVersion>
 		<OutputType>Library</OutputType>
@@ -14,7 +14,7 @@
 		<Description>JavaScript Engine Switcher determines unified interface for access to the basic features of popular JavaScript engines (MSIE JavaScript Engine for .NET, Microsoft ClearScript.V8, Jurassic, Jint, ChakraCore, VroomJs and NiL.JS). This library allows you to quickly and easily switch to using of another JavaScript engine.</Description>
 		<PackageIconUrl>https://raw.githubusercontent.com/Taritsyn/JavaScriptEngineSwitcher/master/Icons/JavaScriptEngineSwitcher_Core_Logo128x128.png</PackageIconUrl>
 		<PackageTags>JavaScriptEngineSwitcher;JavaScript;ECMAScript</PackageTags>
-		<PackageReleaseNotes>Fixed a error #54 “System.Runtime.InteropServices.RuntimeInformation not required for .NET Framework 4.7.1”. Special thanks to David Gardiner.</PackageReleaseNotes>
+		<PackageReleaseNotes>Fixed a error #59 “Unhandled exception when JS exception is thrown”.</PackageReleaseNotes>
 	</PropertyGroup>
 
 	<Import Project="../../build/common.props" />

Diff for: src/JavaScriptEngineSwitcher.Core/readme.txt

@@ -1,7 +1,7 @@
 
 
    --------------------------------------------------------------------------------
-                README file for JS Engine Switcher: Core v3.0.0 Beta 4
+                README file for JS Engine Switcher: Core v3.0.0 Beta 9
 
    --------------------------------------------------------------------------------
 
@@ -20,8 +20,7 @@
    =============
    RELEASE NOTES
    =============
-   Fixed a error #54 “System.Runtime.InteropServices.RuntimeInformation not
-   required for .NET Framework 4.7.1”. Special thanks to David Gardiner.
+   Fixed a error #59 “Unhandled exception when JS exception is thrown”.
 
    =============
    DOCUMENTATION

Diff for: test/JavaScriptEngineSwitcher.Tests/ErrorFormattingTests.cs

@@ -0,0 +1,74 @@
+using Xunit;
+
+using JavaScriptEngineSwitcher.Core.Helpers;
+
+namespace JavaScriptEngineSwitcher.Tests
+{
+	public class ErrorFormattingTests
+	{
+		[Fact]
+		public void GettingSourceFragmentFromLineIsCorrect()
+		{
+			// Arrange
+			const string input1 = "";
+			const string targetOutput1 = input1;
+
+			const string input2 = "	    \n";
+			const string targetOutput2 = input2;
+
+			const string input3 = "var @variable3 = 678;";
+			const string targetOutput3 = input3;
+
+			const string input4 = "	Math.hasOwnProperty(\"log2\")||(Math.log2=function(n){" +
+				"return Math.log(@n)*Math.LOG2E});";
+			const string targetOutput4 = "…Math.hasOwnProperty(\"log2\")||(Math.log2=function(n){" +
+				"return Math.log(@n)*Math.LOG2E});";
+
+			const string input5 = "function mix(destination,source){var propertyName;destination=destination||{};" +
+				"for(propertyName in source){if(source.hasOwnProperty(propertyName){" +
+				"destination[propertyName]=source[propertyName]}}return destination}"
+				;
+			const string targetOutput5 = "… in source){if(source.hasOwnProperty(propertyName){" +
+				"destination[propertyName]=source[propertyName]}}r…";
+
+			const string input6 = "Object.hasOwnProperty(\"assign)||(Object.assign=function(n){" +
+				"var u,i,f,t,r;if(typeof n==\"undefined\"||n===null)" +
+				"throw new TypeError(\"Object.assign: argument is not an Object.\");" +
+				"for(u=Object(n),f=arguments.length,i=1;i<f;i++)" +
+				"if(t=arguments[i],typeof t!=\"undefined\"&&t!==null)for(r in t)" +
+				"Object.prototype.hasOwnProperty.call(t,r)&&(u[r]=t[r]);return u});"
+				;
+			const string targetOutput6 = "Object.hasOwnProperty(\"assign)||(Object.assign=function(n){" +
+				"var u,i,f,t,r;if(typeof n==\"undefined\"||n…";
+
+			const string input7 = "function base64_encode(a){" +
+				"var b=\"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\";" +
+				"var c,o2,o3,h1,h2,h3,h4,bits,i=0,enc='';do{c=a.charCodeAt(i++);o2=a.charCodeAt(i++);" +
+				"o3=a.charCodeAt(i++);bits=c<<16|o2<<8|o3;h1=bits>>18&0x3f;h2=bits>>12&0x3f;" +
+				"h3=bits>>6&0x3f;h4=bits&0x3f;enc+=b.charAt(h1)+b.charAt(h2)+b.charAt(h3)+b.charAt(h4)}" +
+				"while(i<a.length);switch(a.length%3){case 1:enc=enc.slice(0,-2)+'==';break;" +
+				"case 2:enc=enc.slice(0,-1)+'=';break}return @enc}"
+				;
+			const string targetOutput7 = "…(a.length%3){case 1:enc=enc.slice(0,-2)+'==';break;" +
+				"case 2:enc=enc.slice(0,-1)+'=';break}return @enc}";
+
+			// Act
+			string output1 = JsErrorHelpers.GetSourceFragmentFromLine(input1, 1, 100);
+			string output2 = JsErrorHelpers.GetSourceFragmentFromLine(input2, 1, 100);
+			string output3 = JsErrorHelpers.GetSourceFragmentFromLine(input3, 5, 100);
+			string output4 = JsErrorHelpers.GetSourceFragmentFromLine(input4, 70, 85);
+			string output5 = JsErrorHelpers.GetSourceFragmentFromLine(input5, 145, 100);
+			string output6 = JsErrorHelpers.GetSourceFragmentFromLine(input6, 23, 100);
+			string output7 = JsErrorHelpers.GetSourceFragmentFromLine(input7, 465, 100);
+
+			// Assert
+			Assert.Equal(targetOutput1, output1);
+			Assert.Equal(targetOutput2, output2);
+			Assert.Equal(targetOutput3, output3);
+			Assert.Equal(targetOutput4, output4);
+			Assert.Equal(targetOutput5, output5);
+			Assert.Equal(targetOutput6, output6);
+			Assert.Equal(targetOutput7, output7);
+		}
+	}
+}