Fix outputPath check for node < 0.12 and node < 5.0 for Windows

`path.isAbsolute` does not work on node < 0.12
Also, since node v5 `path.isAbsolute` returns true for `/` (which we want),
but for older versions it does not.

Fixes #132 and comment in e896293

middleware.js

@@ -5,7 +5,7 @@
 var MemoryFileSystem = require("memory-fs");
 var mime = require("mime");
 var parseRange = require("range-parser");
-var path = require("path");
+var pathIsAbsolute = require("path-is-absolute");
 var getFilenameFromUrl = require("./lib/GetFilenameFromUrl");
 var pathJoin = require("./lib/PathJoin");
 
@@ -56,7 +56,8 @@ module.exports = function(compiler, options) {
 			options.filename = new RegExp("^[\/]{0,1}" + str + "$");
 		}
 	}
-	if(typeof compiler.outputPath === "string" && !path.isAbsolute(compiler.outputPath)) {
+	if(typeof compiler.outputPath === "string" &&
+		!pathIsAbsolute.posix(compiler.outputPath) && !pathIsAbsolute.win32(compiler.outputPath)) {
 		throw new Error("`output.path` needs to be an absolute path or `/`.");
 	}
 

package.json

@@ -9,6 +9,7 @@
   "dependencies": {
     "memory-fs": "~0.3.0",
     "mime": "^1.3.4",
+    "path-is-absolute": "^1.0.0",
     "range-parser": "^1.0.3"
   },
   "devDependencies": {

test/FileSystem.test.js

@@ -34,4 +34,10 @@ describe("FileSystem", function() {
 			middleware(compiler);
 		}, /output\.path/);
 	});
+
+	it("should not throw on valid outputPath config for Windows", function() {
+		var compiler = fakeWebpack();
+		compiler.outputPath = "C:/my/path";
+		middleware(compiler);
+	});
 });