add some monkeypatched istanbul interop - closes #660

lib/6to5/register.js

@@ -34,7 +34,6 @@ var cache = registerCache.get();
 var transformOpts = {};
 var ignoreRegex   = /node_modules/;
 var onlyRegex;
-var whitelist     = [];
 var exts          = {};
 var maps          = {};
 var old           = require.extensions[".js"];
@@ -43,11 +42,7 @@ var mtime = function (filename) {
   return +fs.statSync(filename).mtime;
 };
 
-var loader = function (m, filename) {
-  if ((ignoreRegex && ignoreRegex.test(filename)) || (onlyRegex && !onlyRegex.test(filename))) {
-    return old.apply(this, arguments);
-  }
-
+var compile = function (filename) {
   var result;
 
   if (cache) {
@@ -57,11 +52,12 @@ var loader = function (m, filename) {
     }
   }
 
-  result = result || to5.transformFileSync(filename, extend({
-    whitelist: whitelist,
-    sourceMap: true,
-    ast:       false
-  }, transformOpts));
+  if (!result) {
+    result = to5.transformFileSync(filename, extend({
+      sourceMap: true,
+      ast:       false
+    }, transformOpts));
+  }
 
   if (cache) {
     result.mtime = mtime(filename);
@@ -70,7 +66,44 @@ var loader = function (m, filename) {
 
   maps[filename] = result.map;
 
-  m._compile(result.code, filename);
+  return result.code;
+};
+
+var shouldIgnore = function (filename) {
+  console.log(filename);
+  return (ignoreRegex && ignoreRegex.test(filename)) || (onlyRegex && !onlyRegex.test(filename));
+};
+
+var istanbulLoader = function (m, filename, old) {
+  // we need to monkey patch fs.readFileSync so we can hook into
+  // what istanbul gets, it's extremely dirty but it's the only way
+  var _readFileSync = fs.readFileSync;
+
+  fs.readFileSync = function () {
+    fs.readFileSync = _readFileSync;
+    return compile(filename);
+  };
+
+  old(m, filename);
+};
+
+var normalLoader = function (m, filename) {
+  m._compile(compile(filename), filename);
+};
+
+var registerExtension = function (ext) {
+  var old = require.extensions[ext];
+
+  var loader = normalLoader;
+  if (process.env.running_under_istanbul) loader = istanbulLoader;
+
+  require.extensions[ext] = function (m, filename) {
+    if (shouldIgnore(filename)) {
+      old(m, filename);
+    } else {
+      loader(m, filename, old);
+    }
+  };
 };
 
 var hookExtensions = function (_exts) {
@@ -82,7 +115,7 @@ var hookExtensions = function (_exts) {
 
   each(_exts, function (ext) {
     exts[ext] = require.extensions[ext];
-    require.extensions[ext] = loader;
+    registerExtension(ext);
   });
 };