fix bundling; closes #3091

This became too difficult to manage on the command-line.

What we're trying to do here is ship a version of the `Buffer` shim
which plays well with IE9/IE10.  Browserify ships with a version which
does NOT play well, meaning we have to force it to use the version
we choose (`buffer@4.9.x`).

The fix is in two parts:

1.  `insertGlobalVars` option replaces usages of global `Buffer` with
`require('/path/to/mocha/node_modules/buffer').Buffer`
2.  Any *other* module which explicitly requires `buffer` or, yes,
`buffer/`, must *also* use `/path/to/mocha/node_modules/buffer`

If *both* of these are not in place, Browserify will use its *own*
version of the `buffer` shim.

Makefile

@@ -1,4 +1,4 @@
-BROWSERIFY := "node_modules/.bin/browserify"
+BROWSERIFY := "scripts/build.js"
 KARMA := "node_modules/.bin/karma"
 MOCHA := "bin/mocha"
 NYC := "node_modules/.bin/nyc"
@@ -20,13 +20,7 @@ all: mocha.js
 mocha.js: $(SRC) browser-entry.js
 	@printf "==> [Browser :: build]\n"
 	mkdir -p ${@D}
-	$(BROWSERIFY) ./browser-entry \
-		--require buffer/:buffer \
-		--plugin ./scripts/dedefine \
-		--ignore 'fs' \
-		--ignore 'glob' \
-		--ignore 'path' \
-		--ignore 'supports-color' > $@
+	$(BROWSERIFY) > $@
 
 clean:
 	@printf "==> [Clean]\n"

karma.conf.js

@@ -4,6 +4,9 @@ var fs = require('fs');
 var path = require('path');
 var mkdirp = require('mkdirp');
 var baseBundleDirpath = path.join(__dirname, '.karma');
+var builder = require('./scripts/build');
+var build = builder.build;
+var bundlerOptions = builder.options;
 
 var browserPlatformPairs = {
   'chrome@latest': 'Windows 8',
@@ -32,23 +35,20 @@ module.exports = function (config) {
     preprocessors: {
       'test/**/*.js': ['browserify']
     },
-    browserify: {
-      debug: true,
-      configure: function configure (b) {
-        b.ignore('glob')
-          .ignore('fs')
-          .ignore('path')
-          .ignore('supports-color')
-          .require(path.join(__dirname, 'node_modules', 'buffer'), {expose: 'buffer'})
-          .on('bundled', function (err, content) {
-            if (!err && bundleDirpath) {
-              // write bundle to directory for debugging
-              fs.writeFileSync(path.join(bundleDirpath,
-                'bundle.' + Date.now() + '.js'), content);
-            }
-          });
-      }
-    },
+    browserify: Object.assign({insertGlobalVars: bundlerOptions.insertGlobalVars},
+      {
+        debug: true,
+        configure: function configure (b) {
+          build(b)
+            .on('bundled', function (err, content) {
+              if (!err && bundleDirpath) {
+                // write bundle to directory for debugging
+                fs.writeFileSync(path.join(bundleDirpath, 'bundle.' +
+                  Date.now() + '.js'), content);
+              }
+            });
+        }
+      }),
     reporters: ['mocha'],
     colors: true,
     browsers: ['PhantomJS'],

package.json

@@ -321,6 +321,7 @@
     "supports-color": "4.4.0"
   },
   "devDependencies": {
+    "aliasify": "^2.1.0",
     "assert": "^1.4.1",
     "browserify": "^14.4.0",
     "buffer": "^4.9.1",

scripts/build.js

@@ -0,0 +1,46 @@
+#!/usr/bin/env node
+'use strict';
+
+/**
+ * Mocha's build script which is sadly too complex to manage from the command
+ * line
+ * @type {Browserify}
+ */
+
+const browserify = require('browserify');
+const path = require('path');
+const dedefine = require('./dedefine');
+const aliasify = require('aliasify');
+
+const options = {
+  basedir: path.join(__dirname, '..'),
+  entries: ['./browser-entry.js'],
+  insertGlobalVars: {
+    Buffer (file, basedir) {
+      const filepath = path.join(path.relative(path.dirname(file), basedir),
+        'node_modules',
+        'buffer');
+      return `require('${filepath}').Buffer`;
+    }
+  }
+};
+
+const build = (b) => b.ignore('fs')
+  .ignore('glob')
+  .ignore('path')
+  .ignore('supports-color')
+  .transform(aliasify, {
+    replacements: {
+      '^buffer/?': () => require.resolve('buffer/index.js')
+    },
+    global: true
+  })
+  .plugin(dedefine);
+
+exports.build = build;
+exports.options = options;
+
+if (require.main === module) {
+  build(browserify(options)).bundle()
+    .pipe(process.stdout);
+}