set package.json#browserify#transform as fallback option

bin/advanced.txt

@@ -61,10 +61,13 @@ Advanced Options:
     Instead of the default package.json#browserify#transform field to list
     all transforms to apply when running browserify, a custom field, like, e.g.
     package.json#browserify#production or package.json#browserify#staging
-    can be used, by for example running:
+    can be used by running:
     * `browserify index.js --transform-key=production > bundle.js`
     * `browserify index.js --transform-key=staging > bundle.js`
 
+    if dependency doesn't specify the custom field, it falls back to
+    package.json#browserify#transform for that dependency
+
   --node
 
     Alias for --bare and --no-browser-field.
@@ -110,4 +113,3 @@ Passing arguments to transforms and plugins:
   will call the `foo` transform for each applicable file by calling:
 
     foo(file, { x: 3, beep: true })
-

index.js

@@ -434,7 +434,8 @@ Browserify.prototype._createDeps = function (opts) {
     self._extensions = mopts.extensions;
 
     mopts.transform = [];
-    mopts.transformKey = defined(opts.transformKey, [ 'browserify', 'transform' ]);
+    mopts.defaultTransformKey = [ 'browserify', 'transform' ];
+    mopts.transformKey = defined(opts.transformKey, mopts.defaultTransformKey);
     mopts.postFilter = function (id, file, pkg) {
         if (opts.postFilter && !opts.postFilter(id, file, pkg)) return false;
         if (self._external.indexOf(file) >= 0) return false;