Support folder modules, i.e. if you don't find a module at location, …

…look for it at location/index.js

require.js

@@ -26,57 +26,62 @@ if (typeof require == 'undefined') (function() {
 			}
 		}
 
-		return pathParts.join('/') + '.js'
+		var possiblesBase = pathParts.join('/')
+		return [possiblesBase + '.js', possiblesBase + '/index.js']
 	}
 
 	// IE6 won't return an anonymous function from eval, so use the function constructor instead
 	var evaluate = typeof eval('(function(){})') == 'undefined'
 		? function(src, path) { return (new Function('return ' + src))() }
 		: function(src, path) { var src = src + '\n//@ sourceURL=' + path; return eval(src) }
 
-	var fetchFile = function(path) {
-		path = location.protocol + '//' + location.host + path
-		var xhr = new XHR()
-		try {
-			xhr.open('GET', path, false)
-			xhr.send(null)
-		} catch(e) {
-			log(path, 'fetchFile open/send error:', e)
-			return null // firefox file://
-		}
-
-		if (xhr.status == 404 || // all browsers, http://
-			xhr.status == -1100) { // safari file://
-			// XXX: We have no way to tell in opera if a file exists and is empty, or is 404
-			log(path, 'fetchFile xhr.status error:', xhr.status)
-			return null
+	var fetchFile = function(possiblePaths) {
+		while (possiblePaths.length) {
+			var possiblePath = possiblePaths[0],
+				url = location.protocol + '//' + location.host + possiblePath,
+				xhr = new XHR()
+			try {
+				xhr.open('GET', url, false)
+				xhr.send(null)
+			} catch(e) {
+				log(url, 'fetchFile open/send error:', e)
+			}
+
+			if (xhr.status == -1100) { // safari file://
+				// XXX: We have no way to tell in opera if a file exists and is empty, or is 404
+				log(url, 'fetchFile xhr.status error:', xhr.status)
+			} else if (xhr.status < 400) {
+				return xhr.responseText;
+			}
+			possiblePaths.shift()
 		}
-
-		return xhr.responseText;
+		return null
 	}
 
 	var pageBasePath = location.pathname.replace(/\/[^\/]*$/, '/')
 	window.require = function(modulePath) {
 		var baseStack = require._base,
 			currentBase = baseStack[baseStack.length - 1] || require._root || pageBasePath,
-			path = resolvePath(currentBase, modulePath)
+			possiblePaths = resolvePath(currentBase, modulePath)
 
-		if (require._modules[path]) { return require._modules[path] }
-		require._base.push(getDir(path))
+		for (var i=0, path; path = possiblePaths[i]; i++) {
+			if (require._modules[path]) { return require._modules[path] }
+		}
 
-		var moduleCode = fetchFile(path),
-			moduleFriendlyName = path.replace(/[\/.]/g, '_')
+		var moduleCode = fetchFile(possiblePaths),
+			foundPath = possiblePaths[0] // fetchFile will remove bad paths from possiblePaths
 
-		if (!moduleCode) {
+		if (!foundPath) {
 			log(path, 'failed to load module', modulePath)
 			return
 		}
-
+		require._base.push(getDir(foundPath))
+		var moduleFriendlyName = foundPath.replace(/[\/.]/g, '_')
 		try {
 			var inContextCode = '(function(module){ var exports = module.exports;\n'+ moduleCode +'\n})',
-				importerFunction = evaluate(inContextCode, path)
+				importerFunction = evaluate(inContextCode, foundPath)
 		} catch(e) {
-			if(e instanceof SyntaxError) { log(path, 'a syntax error prevented execution') }
+			if(e instanceof SyntaxError) { log(foundPath, 'a syntax error prevented execution') }
 			throw e
 		}
 
@@ -86,20 +91,20 @@ if (typeof require == 'undefined') (function() {
 			importerFunction(moduleObject)
 		} catch(e) {
 			if(e.type == 'syntax_error') {
-				log(path, 'Syntax error while importing module', e)
+				log(foundPath, 'Syntax error while importing module', e)
 				throw e
 			} else if (!e.requireLogged) {
 				e.requireLogged = true
 				if (e.type == 'stack_overflow') {
-					log(path, 'Stack overflow while importing module', path, e)
+					log(foundPath, 'Stack overflow while importing module', e)
 				} else {
-					log(path, 'enable "break on error" in your debugger to debug', e)
+					log(foundPath, 'enable "break on error" in your debugger to debug', e)
 				}
 				throw e
 			}
 		}
 
-		require._modules[path] = moduleObject.exports
+		require._modules[foundPath] = moduleObject.exports
 		require._base.pop()
 		return moduleObject.exports
 	}

test/subfolder/moduleB.js

@@ -4,3 +4,5 @@ var moduleC = require('./moduleC'),
 exports.somethingFromModuleC = moduleC.something
 exports.somethingFromModuleD = moduleD.something
 exports.something = 'exports in moduleB'
+
+exports.folderModule = require('./folder-module')