Returned error treated when requesting uncommon URL (#3544)

* Fixing error returned when requesting illegal URL

* Adding unit tests http.js

* Fixing error message axios invalid request from browser

* Adding unit tests requests.spec.js

* Adding at utils.js a new method: getProtocol

Co-authored-by: Jay <jasonsaayman@gmail.com>

lib/utils.js

@@ -6,6 +6,22 @@ var bind = require('./helpers/bind');
 
 var toString = Object.prototype.toString;
 
+/**
+ * Array with axios supported protocols.
+ */
+var supportedProtocols = [ 'http:', 'https:', 'file:' ];
+
+/**
+ * Returns URL protocol passed as param if is not undefined or null,
+ * otherwise just returns 'http:'
+ *
+ * @param {String} protocol The String value of URL protocol
+ * @returns {String} Protocol if the value is not undefined or null
+ */
+function getProtocol(protocol) {
+  return protocol || 'http:';
+}
+
 /**
  * Determine if a value is an Array
  *
@@ -324,6 +340,8 @@ function stripBOM(content) {
 }
 
 module.exports = {
+  supportedProtocols: supportedProtocols,
+  getProtocol: getProtocol,
   isArray: isArray,
   isArrayBuffer: isArrayBuffer,
   isBuffer: isBuffer,