Correctly initialize Node environment in worker

lib/worker/init.js

@@ -0,0 +1,37 @@
+'use strict'
+
+const path = require('path')
+const Module = require('module')
+
+// We modified the original process.argv to let node.js load the
+// init.js, we need to restore it here.
+process.argv.splice(1, 1)
+
+// Clear search paths.
+require('../common/reset-search-paths')
+
+// Import common settings.
+require('../common/init')
+
+// Expose public APIs.
+Module.globalPaths.push(path.join(__dirname, 'api', 'exports'))
+
+// Export node bindings to global.
+global.require = require
+global.module = module
+
+// Set the __filename to the path of html file if it is file: protocol.
+if (self.location.protocol === 'file:') {
+  let pathname = process.platform === 'win32' && self.location.pathname[0] === '/' ? self.location.pathname.substr(1) : self.location.pathname
+  global.__filename = path.normalize(decodeURIComponent(pathname))
+  global.__dirname = path.dirname(global.__filename)
+
+  // Set module's filename so relative require can work as expected.
+  module.filename = global.__filename
+
+  // Also search for module under the html file.
+  module.paths = module.paths.concat(Module._nodeModulePaths(global.__dirname))
+} else {
+  global.__filename = __filename
+  global.__dirname = __dirname
+}