From 035829e7262489d8698036e291eb8027621752da Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Wed, 22 Oct 2014 21:43:43 +1100
Subject: [PATCH] add custom module formatters

---
 MODULES.md       | 28 ++++++++++++++++++++++++++++
 lib/6to5/file.js | 11 ++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/MODULES.md b/MODULES.md
index a75ada8cb9..8f8980169c 100644
--- a/MODULES.md
+++ b/MODULES.md
@@ -108,3 +108,31 @@ export function bar() {
   }
 });
 ```
+
+## Custom
+
+```javascript
+module.exports = ModuleFormatter;
+
+function ModuleFormatter() {
+
+}
+
+ModuleFormatter.prototype.import = function (node, nodes) {
+  // node is an ImportDeclaration
+};
+
+ModuleFormatter.prototype.importSpecifier = function (specifier, node, nodes) {
+  // specifier is an ImportSpecifier
+  // node is an ImportDeclaration
+};
+
+ModuleFormatter.prototype.export = function (node, nodes) {
+  // node is an ExportDeclaration
+};
+
+ModuleFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
+  // specifier is an ExportSpecifier
+  // node is an ExportDeclaration
+};
+```
diff --git a/lib/6to5/file.js b/lib/6to5/file.js
index 8f9dcb53f3..aefbfa2903 100644
--- a/lib/6to5/file.js
+++ b/lib/6to5/file.js
@@ -41,7 +41,16 @@ File.normaliseOptions = function (opts) {
 
 File.prototype.getModuleFormatter = function (type) {
   var ModuleLoader = transform.moduleFormatters[type];
-  if (!ModuleLoader) throw new ReferenceError("unknown module formatter type " + type);
+
+  if (!ModuleLoader) {
+    var loc = util.resolve(type)
+    if (loc) ModuleLoader = require(loc);
+  }
+
+  if (!ModuleLoader) {
+    throw new ReferenceError("unknown module formatter type " + type);
+  }
+
   return new ModuleLoader(this);
 };