Rename mergeConfig arguments

lib/core/mergeConfig.js

@@ -6,28 +6,28 @@ var utils = require('../utils');
  * Config-specific merge-function which creates a new config-object
  * based on given defaults and instance config.
  *
- * @param {Object} defaults Defaults
- * @param {Object} instanceConfig Instance-specific config
- * @returns {Object} New object resulting from merging instanceConfig to defaults
+ * @param {Object} config1
+ * @param {Object} config2
+ * @returns {Object} New object resulting from merging config2 to config1
  */
-module.exports = function mergeConfig(defaults, instanceConfig) {
+module.exports = function mergeConfig(config1, config2) {
   // eslint-disable-next-line no-param-reassign
-  instanceConfig = instanceConfig || {};
+  config2 = config2 || {};
   var config = {};
 
   utils.forEach(['url', 'method', 'params', 'data'], function valueFromInstanceConfig(prop) {
-    config[prop] = instanceConfig[prop];
+    config[prop] = config2[prop];
   });
 
   utils.forEach(['headers', 'auth', 'proxy'], function mergeInstanceConfigWithDefaults(prop) {
-    if (typeof instanceConfig[prop] !== 'undefined') {
-      if (typeof instanceConfig[prop] === 'object') {
-        config[prop] = utils.deepMerge(defaults[prop], instanceConfig[prop]);
+    if (typeof config2[prop] !== 'undefined') {
+      if (typeof config2[prop] === 'object') {
+        config[prop] = utils.deepMerge(config1[prop], config2[prop]);
       } else {
-        config[prop] = instanceConfig[prop];
+        config[prop] = config2[prop];
       }
-    } else if (typeof defaults[prop] !== 'undefined') {
-      config[prop] = utils.deepMerge(defaults[prop]);
+    } else if (typeof config1[prop] !== 'undefined') {
+      config[prop] = utils.deepMerge(config1[prop]);
     }
   });
 
@@ -37,7 +37,7 @@ module.exports = function mergeConfig(defaults, instanceConfig) {
     'xsrfHeaderName', 'onUploadProgress', 'onDownloadProgress', 'maxContentLength',
     'validateStatus', 'maxRedirects', 'httpAgent', 'httpsAgent', 'cancelToken'
   ], function defaultToInstanceConfig(prop) {
-    config[prop] = typeof instanceConfig[prop] === 'undefined' ? defaults[prop] : instanceConfig[prop];
+    config[prop] = typeof config2[prop] === 'undefined' ? config1[prop] : config2[prop];
   });
 
   return config;