fix(index): enable HMR in case locals (css-modules) are unchanged (…

…#298)

index.js

@@ -23,13 +23,22 @@ module.exports.pitch = function (request) {
 		"// Hot Module Replacement",
 		"if(module.hot) {",
 		"	// When the styles change, update the <style> tags",
-		"	if(!content.locals) {",
-		"		module.hot.accept(" + loaderUtils.stringifyRequest(this, "!!" + request) + ", function() {",
-		"			var newContent = require(" + loaderUtils.stringifyRequest(this, "!!" + request) + ");",
-		"			if(typeof newContent === 'string') newContent = [[module.id, newContent, '']];",
-		"			update(newContent);",
-		"		});",
-		"	}",
+		"	module.hot.accept(" + loaderUtils.stringifyRequest(this, "!!" + request) + ", function() {",
+		"		var newContent = require(" + loaderUtils.stringifyRequest(this, "!!" + request) + ");",
+		"		if(typeof newContent === 'string') newContent = [[module.id, newContent, '']];",
+		"		var locals = (function(a, b) {",
+		"			var key, idx = 0;",
+		"			for(key in a) {",
+		"				if(!b || a[key] !== b[key]) return false;",
+		"				idx++;",
+		"			}",
+		"			for(key in b) idx--;",
+		"			return idx === 0;",
+		"		}(content.locals, newContent.locals));",
+		"		// This error is caught and not shown and causes a full reload.",
+		"		if(!locals) throw new Error('Aborting CSS HMR due to changed css-modules locals.');",
+		"		update(newContent);",
+		"	});",
 		"	// When the module is disposed, remove the <style> tags",
 		"	module.hot.dispose(function() { update(); });",
 		"}"