Make Babel 7 the default

Fixes reactjs#798

Author: Dustin Masters

src/React.Core/Babel.cs

@@ -74,7 +74,7 @@ public Babel(IReactEnvironment environment, ICache cache, IFileSystem fileSystem
 			_fileSystem = fileSystem;
 			_fileCacheHash = fileCacheHash;
 			_config = siteConfig;
-			_babelConfig = siteConfig.BabelConfig.Serialize(_config.BabelVersion);
+			_babelConfig = siteConfig.BabelConfig.Serialize(_config.BabelVersion ?? BabelVersions.Babel7);
 		}
 
 		/// <summary>
@@ -250,7 +250,7 @@ protected virtual JavaScriptWithSourceMap TransformWithHeader(
 		/// <param name="input">JavaScript</param>
 		/// <param name="filename">Name of the file being transformed</param>
 		/// <returns>JavaScript</returns>
-		public virtual string Transform(string input, string filename = "unknown")
+		public virtual string Transform(string input, string filename = "unknown.jsx")
 		{
 			try
 			{

src/React.Core/IBabel.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright (c) Facebook, Inc. and its affiliates.
  *
  * This source code is licensed under the MIT license found in the
@@ -40,7 +40,7 @@ JavaScriptWithSourceMap TransformFileWithSourceMap(
 		/// <param name="input">JavaScript</param>
 		/// <param name="filename">Name of the file being transformed</param>
 		/// <returns>JavaScript</returns>
-		string Transform(string input, string filename = "unknown");
+		string Transform(string input, string filename = "unknown.jsx");
 
 		/// <summary>
 		/// Transforms JavaScript via Babel and also returns a source map to map the compiled

src/React.Core/ReactEnvironment.cs

@@ -480,9 +480,9 @@ private void EnsureBabelLoaded(IJsEngine engine)
 #else
 				var assembly = typeof(ReactEnvironment).GetTypeInfo().Assembly;
 #endif
-				string resourceName = _config.BabelVersion == BabelVersions.Babel7
+				string resourceName = _config.BabelVersion == BabelVersions.Babel7 || _config.BabelVersion == null
 					? "React.Core.Resources.babel.generated.min.js"
-					: _config.BabelVersion == BabelVersions.Babel6 || _config.BabelVersion == null
+					: _config.BabelVersion == BabelVersions.Babel6
 						? "React.Core.Resources.babel-legacy.generated.min.js"
 						: throw new ReactConfigurationException("BabelVersion was not null, but did not contain a valid value.");
 

tests/React.Tests.Integration/ServerRenderTests.cs

@@ -80,14 +80,12 @@ public void RendersPrecompiledScript(bool withPrecompilation)
 			}
 		}
 
-		[Theory]
-		[InlineData(null)]
-		[InlineData("babel-6")]
-		public void BabelTransformsJSX(string babelVersion)
+		[Fact]
+		public void Babel6TransformsJSX()
 		{
 			ReactEnvironment.Current.Configuration
 				.SetLoadBabel(true)
-				.SetBabelVersion(babelVersion);
+				.SetBabelVersion(BabelVersions.Babel6);
 
 			Assert.Equal(@"React.createElement(
   ""div"",
@@ -96,6 +94,18 @@ public void BabelTransformsJSX(string babelVersion)
 );", ReactEnvironment.Current.Babel.Transform("<div>Hello</div>"));
 		}
 
+		[Theory]
+		[InlineData(null)]
+		[InlineData("babel-7")]
+		public void BabelTransformsJSX(string babelVersion)
+		{
+			ReactEnvironment.Current.Configuration
+				.SetLoadBabel(true)
+				.SetBabelVersion(babelVersion);
+
+			Assert.Equal(@"React.createElement(""div"", null, ""Hello"");", ReactEnvironment.Current.Babel.Transform("<div>Hello</div>"));
+		}
+
 		[Fact]
 		public void BabelTransformsTypescript()
 		{

tests/React.Tests/Core/BabelTransformerTests.cs

@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright (c) Facebook, Inc. and its affiliates.
  *
  * This source code is licensed under the MIT license found in the
@@ -53,7 +53,7 @@ public void ShouldTransformJsx()
 				"ReactNET_transform",
 				"<div>Hello World</div>",
 				It.IsAny<string>(),
-				"unknown" // file name
+				"unknown.jsx" // file name
 			));
 		}
 
@@ -64,7 +64,7 @@ public void ShouldWrapExceptionsInJsxExeption()
 				"ReactNET_transform",
 				"<div>Hello World</div>",
 				It.IsAny<string>(),
-				"unknown" // file name
+				"unknown.jsx" // file name
 			)).Throws(new Exception("Something broke..."));
 
 			const string input = "<div>Hello World</div>";