Improve packaging and split browser and Node-specific code

This commit separates components that depend on browser environment
from components that use Node features. No separation was previously
needed because code used runtime feature detection. Such feature
detection made it impossible for bundlers, like Webpack, to strip
away Node-specific code. Presence of it caused failures at build time
and made it hard to use the driver package.

Driver contains couple env-dependent components:
 * network channel (`WebSocket` in browser, `net.Socket` in Node)
 * byte buffer (`ArrayBuffer` in browser, `buffer.Buffer` in Node)
 * host name resolver (no-op in browser, `dns` lookup in Node)
 * UTF8 encoding & decoding (`text-encoding` library in browser, `StringDecoder` in Node)

Implementations of these components now live in separate folders
`src/internal/node` and `src/internal/browser`. Both contain `index.js`
files that export the same set of components and follow the same
"interface". Env-dependent tests are also split into separate folders.
All sources import/require `node/index.js` by default.

`package.json` now contains a "browser" field which instructs bundlers
to replace all imports/require of `node/index.js` with `browser/index.js`
for client-side apps. This way code that depends on Node APIs will not
even be included in the resulting bundle.

Gulp build for UMD `neo4j-web.js` and `neo4j-web.test.js` bundles
excludes `node` folders and only includes `browser`. It also replaces
all require calls of "/node" to "/browser". Dedicated browserify
transformation is added for this to the bundling process. Resulting
bundles no longer contain code that depends on Node APIs.

Author: lutovich

gulpfile.babel.js

@@ -45,6 +45,7 @@ var sharedNeo4j = require('./test/internal/shared-neo4j').default;
 var ts = require('gulp-typescript');
 var JasmineConsoleReporter = require('jasmine-console-reporter');
 var karmaServer = require('karma').Server;
+var transformTools = require('browserify-transform-tools');
 
 /**
  * Useful to investigate resource leaks in tests. Enable to see active sockets and file handles after the 'test' task.
@@ -66,9 +67,9 @@ gulp.task('build-browser', function () {
     cache: {},
     standalone: 'neo4j',
     packageCache: {}
-  }).transform(babelify.configure({
-    presets: ['env'], ignore: /external/
-  })).bundle();
+  }).transform(babelify.configure({presets: ['env'], ignore: /external/}))
+    .transform(browserifyTransformNodeToBrowserRequire())
+    .bundle();
 
   // Un-minified browser package
   appBundler
@@ -87,7 +88,7 @@ gulp.task('build-browser', function () {
 gulp.task('build-browser-test', function(){
   var browserOutput = 'lib/browser/';
   var testFiles = [];
-  return gulp.src('./test/**/*.test.js')
+  return gulp.src(['./test/**/*.test.js', '!./test/**/node/*.js'])
     .pipe( through.obj( function( file, enc, cb ) {
       if(file.path.indexOf('examples.test.js') < 0) {
         testFiles.push( file.path );
@@ -106,6 +107,7 @@ gulp.task('build-browser-test', function(){
         }).transform(babelify.configure({
         presets: ['env'], plugins: ['transform-runtime'], ignore: /external/
         }))
+        .transform(browserifyTransformNodeToBrowserRequire())
         .bundle(function(err, res){
           cb();
         })
@@ -164,7 +166,7 @@ gulp.task('test', function (cb) {
 });
 
 gulp.task('test-nodejs', ['install-driver-into-sandbox'], function () {
-  return gulp.src('test/**/*.test.js')
+  return gulp.src(['./test/**/*.test.js', '!./test/**/browser/*.js'])
     .pipe(jasmine({
       includeStackTrace: true,
       reporter: newJasmineConsoleReporter()
@@ -306,3 +308,21 @@ function newJasmineConsoleReporter() {
     activity: false
   });
 }
+
+function browserifyTransformNodeToBrowserRequire() {
+  var nodeRequire = '/node';
+  var browserRequire = '/browser';
+
+  return transformTools.makeRequireTransform('bodeToBrowserRequireTransform',
+    {evaluateArguments: true},
+    function (args, opts, cb) {
+      var requireArg = args[0];
+      var endsWithNodeRequire = requireArg.slice(-nodeRequire.length) === nodeRequire;
+      if (endsWithNodeRequire) {
+        var newRequireArg = requireArg.replace(nodeRequire, browserRequire);
+        return cb(null, 'require(\'' + newRequireArg + '\')');
+      } else {
+        return cb();
+      }
+    });
+}

package-lock.json

@@ -22,13 +22,7 @@
   },
   "main": "lib/index.js",
   "browser": {
-    "./lib/v1/internal/utf8.js": "./lib/v1/internal/browser/browser-utf8.js",
-    "dns": false,
-    "buffer": false,
-    "net": false,
-    "readline": false,
-    "crypto": false,
-    "tls": false
+    "./lib/v1/internal/node/index.js": "./lib/v1/internal/browser/index.js"
   },
   "unpkg": "lib/browser/neo4j-web.js",
   "jsdelivr": "lib/browser/neo4j-web.js",
@@ -41,6 +35,7 @@
     "babel-register": "^6.26.0",
     "babelify": "^7.3.0",
     "browserify": "^13.3.0",
+    "browserify-transform-tools": "^1.7.0",
     "esdoc": "^1.0.4",
     "esdoc-importpath-plugin": "^1.0.1",
     "esdoc-standard-plugin": "^1.0.0",

package.json

@@ -17,7 +17,7 @@
  * limitations under the License.
  */
 
-import {BaseBuffer} from '../buf';
+import BaseBuffer from '../buf/base-buf';
 
 export default class HeapBuffer extends BaseBuffer {
 

src/v1/internal/browser/browser-buf.js

@@ -17,9 +17,9 @@
  * limitations under the License.
  */
 
-import {HostNameResolver} from '../host-name-resolver';
+import BaseHostNameResolver from '../resolver/base-host-name-resolver';
 
-export default class BrowserHostNameResolver extends HostNameResolver {
+export default class BrowserHostNameResolver extends BaseHostNameResolver {
 
   resolve(address) {
     return this._resolveToItself(address);

src/v1/internal/browser/browser-host-name-resolver.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2002-2018 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import HeapBuffer from './browser-buf';
+import WebSocketChannel from './browser-channel';
+import BrowserHosNameResolver from './browser-host-name-resolver';
+import utf8Codec from './browser-utf8';
+
+export const alloc = arg => new HeapBuffer(arg);
+export const Channel = WebSocketChannel;
+export const HostNameResolver = BrowserHosNameResolver;
+export const utf8 = utf8Codec;