lib: refactor record-serialization.js

Get rid of nested try-catch statements. Decouple `safeRequire` function
that can be used later.

PR-URL: #41

lib/common.js

@@ -25,3 +25,14 @@ common.forwardMultipleEvents = (from, to, eventNames) => {
     common.forwardEvent(from, to, event);
   });
 };
+
+// Try to require `moduleName` and return the exported object if the module is
+// found or null otherwise.
+//
+common.safeRequire = (moduleName) => {
+  try {
+    return require(moduleName);
+  } catch (err) {
+    return null;
+  }
+};

lib/record-serialization.js

@@ -1,5 +1,6 @@
 'use strict';
 
+const safeRequire = require('./common').safeRequire;
 const serializerFactory = require('./serializer-factory');
 
 const jsrs = {};
@@ -11,26 +12,20 @@ module.exports = jsrs;
 // one of our priorities to optimize it.
 const USE_NATIVE_SERIALIZER = false;
 
-let jstpNative;
-
-try {
-  jstpNative = require('../build/Release/jstp');
-} catch (e) {
-  try {
-    jstpNative = require('../build/Debug/jstp');
-  } catch (e) {
-    console.warn(
-      'JSTP native addon is not built. ' +
-      'Run `npm install` in order to build it, otherwise you will get ' +
-      'poor server performance under load.'
-    );
-    module.exports = require('./record-serialization-fallback');
-  }
-}
+const jstpNative =
+  safeRequire('../build/Release/jstp') ||
+  safeRequire('../build/Debug/jstp');
 
 if (jstpNative) {
   Object.assign(jsrs, jstpNative);
   if (!USE_NATIVE_SERIALIZER) {
     jsrs.stringify = serializerFactory.createSerializer();
   }
+} else {
+  console.warn(
+    'JSTP native addon is not built. ' +
+    'Run `npm install` in order to build it, otherwise you will get ' +
+    'poor server performance under load.'
+  );
+  module.exports = require('./record-serialization-fallback');
 }