Improve browserify/webpack support

Gruntfile.js

@@ -138,15 +138,14 @@ module.exports = function(grunt) {
           browserifyOptions: {
             standalone: 'JSZip',
             transform: ['package-json-versionify'],
-            insertGlobalVars : {
-              Buffer: function () {
-                // instead of the full polyfill, we just use the raw value
-                // (or undefined).
-                return '(typeof Buffer !== "undefined" ? Buffer : undefined)';
-              }
-            }
+            insertGlobalVars: {
+                process: undefined,
+                Buffer: undefined,
+                __filename: undefined,
+                __dirname: undefined
+            },
+            builtins: false
           },
-          ignore : ["./lib/nodejs/*"],
           banner : grunt.file.read('lib/license_header.js').replace(/__VERSION__/, version)
         }
       }

lib/external.js

@@ -1,9 +1,15 @@
+/* global Promise */
 'use strict';
 
 // load the global object first:
 // - it should be better integrated in the system (unhandledRejection in node)
 // - the environment may have a custom Promise implementation (see zone.js)
-var ES6Promise = global.Promise || require("lie");
+var ES6Promise = null;
+if (typeof Promise !== "undefined") {
+    ES6Promise = Promise;
+} else {
+    ES6Promise = require("lie");
+}
 
 /**
  * Let the user use/change some implementations.

lib/readable-stream-browser.js

@@ -0,0 +1,9 @@
+/*
+ * This file is used by module bundlers (browserify/webpack/etc) when
+ * including a stream implementation. We use "readable-stream" to get a
+ * consistent behavior between nodejs versions but bundlers often have a shim
+ * for "stream". Using this shim greatly improve the compatibility and greatly
+ * reduce the final size of the bundle (only one stream implementation, not
+ * two).
+ */
+module.exports = require("stream");

lib/stream/StreamHelper.js

@@ -4,9 +4,16 @@ var utils = require('../utils');
 var ConvertWorker = require('./ConvertWorker');
 var GenericWorker = require('./GenericWorker');
 var base64 = require('../base64');
-var NodejsStreamOutputAdapter = require('../nodejs/NodejsStreamOutputAdapter');
+var support = require("../support");
 var external = require("../external");
 
+var NodejsStreamOutputAdapter = null;
+if (support.nodestream) {
+    try {
+        NodejsStreamOutputAdapter = require('../nodejs/NodejsStreamOutputAdapter');
+    } catch(e) {}
+}
+
 /**
  * Apply the final transformation of the data. If the user wants a Blob for
  * example, it's easier to work with an U8intArray and finally do the

lib/support.js

@@ -31,4 +31,8 @@ else {
     }
 }
 
-exports.nodestream = !!require("./nodejs/NodejsStreamOutputAdapter").prototype;
+try {
+    exports.nodestream = !!require('readable-stream').Readable;
+} catch(e) {
+    exports.nodestream = false;
+}

package.json

@@ -24,6 +24,9 @@
     }
   ],
   "main": "./lib/index",
+  "browser": {
+      "readable-stream": "./lib/readable-stream-browser.js"
+  },
   "repository": {
     "type": "git",
     "url": "https://github.com/Stuk/jszip.git"