From d448ecae0ba4ce60733d4729ada035fddc794410 Mon Sep 17 00:00:00 2001
From: Tom Kirkpatrick <tom@systemseed.com>
Date: Mon, 22 Aug 2016 11:00:53 +0200
Subject: [PATCH] Make SendGrid a factory that enables multiple prototype
 instances

---
 lib/sendgrid.js | 79 ++++++++++++++++++++++++++-----------------------
 1 file changed, 42 insertions(+), 37 deletions(-)

diff --git a/lib/sendgrid.js b/lib/sendgrid.js
index eb58f84df..6681d284f 100644
--- a/lib/sendgrid.js
+++ b/lib/sendgrid.js
@@ -64,55 +64,60 @@ function makeHeaders(apiKey, globalHeaders) {
  * SendGrid allows for quick and easy access to the v3 Web API
  */
 function SendGrid(apiKey, host, globalHeaders) {
+  return new SendGridInstance(apiKey, host, globalHeaders);
+}
 
+/**
+ * SendGrid allows for quick and easy access to the v3 Web API
+ */
+function SendGridInstance(apiKey, host, globalHeaders) {
   //Create global request
-  var globalRequest = getEmptyRequest({
+  this.globalRequest = getEmptyRequest({
     host: host || 'api.sendgrid.com',
     headers: makeHeaders(apiKey, globalHeaders),
   });
 
   //Initialize new client
-  var client = new Client(globalRequest);
+  this.client = new Client(this.globalRequest);
+}
 
-  //Interact with the API with this function
-  SendGrid.API = function(request, callback) {
+//Interact with the API with this function
+SendGridInstance.prototype.API = function(request, callback) {
+  var self = this;
 
-    //If no callback provided, we will return a promise
-    if (!callback) {
-      if (!SendGrid.Promise) {
-        throw new SendGridError('Promise API not supported');
-      }
-      return new SendGrid.Promise(function(resolve, reject) {
-        client.API(request, function(response) {
-          if (isValidResponse(response)) {
-            resolve(response);
-          }
-          else {
-            var error = new SendGridError('Response error');
-            error.response = response;
-            reject(error);
-          }
-        });
-      });
+  //If no callback provided, we will return a promise
+  if (!callback) {
+    if (!SendGrid.Promise) {
+      throw new SendGridError('Promise API not supported');
     }
-
-    //Use callback
-    client.API(request, function(response) {
-      if (isValidResponse(response)) {
-        callback(null, response);
-      }
-      else {
-        var error = new SendGridError('Response error');
-        callback(error, response);
-      }
+    return new SendGrid.Promise(function(resolve, reject) {
+      self.client.API(request, function(response) {
+        if (isValidResponse(response)) {
+          resolve(response);
+        }
+        else {
+          var error = new SendGridError('Response error');
+          error.response = response;
+          reject(error);
+        }
+      });
     });
-  };
+  }
 
-  //Set requests
-  SendGrid.emptyRequest = getEmptyRequest;
-  SendGrid.globalRequest = globalRequest;
-  return SendGrid;
-}
+  //Use callback
+  self.client.API(request, function(response) {
+    if (isValidResponse(response)) {
+      callback(null, response);
+    }
+    else {
+      var error = new SendGridError('Response error');
+      callback(error, response);
+    }
+  });
+};
+
+//Set requests
+SendGridInstance.prototype.emptyRequest = getEmptyRequest;
 
 //Try to use native promises by default
 if (typeof Promise !== 'undefined') {