Refactor and introduce deepMerge

lib/axios.js

@@ -3,6 +3,7 @@
 var utils = require('./utils');
 var bind = require('./helpers/bind');
 var Axios = require('./core/Axios');
+var mergeConfig = require('./core/mergeConfig');
 var defaults = require('./defaults');
 
 /**
@@ -32,7 +33,7 @@ axios.Axios = Axios;
 
 // Factory for creating new instances
 axios.create = function create(instanceConfig) {
-  return createInstance(utils.mergeConfig(axios.defaults, instanceConfig));
+  return createInstance(mergeConfig(axios.defaults, instanceConfig));
 };
 
 // Expose Cancel & CancelToken

lib/core/Axios.js

@@ -3,6 +3,7 @@
 var utils = require('./../utils');
 var InterceptorManager = require('./InterceptorManager');
 var dispatchRequest = require('./dispatchRequest');
+var mergeConfig = require('./mergeConfig');
 
 /**
  * Create a new instance of Axios
@@ -32,7 +33,7 @@ Axios.prototype.request = function request(config) {
     config = config || {};
   }
 
-  config = utils.mergeConfig(this.defaults, config);
+  config = mergeConfig(this.defaults, config);
   config.method = config.method ? config.method.toLowerCase() : 'get';
 
   // Hook up interceptors middleware

lib/core/mergeConfig.js

@@ -0,0 +1,44 @@
+'use strict';
+
+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
+ */
+module.exports = function mergeConfig(defaults, instanceConfig) {
+  // eslint-disable-next-line no-param-reassign
+  instanceConfig = instanceConfig || {};
+  var config = {};
+
+  utils.forEach(['url', 'method', 'params', 'data'], function valueFromInstanceConfig(prop) {
+    config[prop] = instanceConfig[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]);
+      } else {
+        config[prop] = instanceConfig[prop];
+      }
+    } else if (typeof defaults[prop] !== 'undefined') {
+      config[prop] = utils.deepMerge(defaults[prop]);
+    }
+  });
+
+  utils.forEach([
+    'baseURL', 'transformRequest', 'transformResponse', 'paramsSerializer',
+    'timeout', 'withCredentials', 'adapter', 'responseType', 'xsrfCookieName',
+    'xsrfHeaderName', 'onUploadProgress', 'onDownloadProgress', 'maxContentLength',
+    'validateStatus', 'maxRedirects', 'httpAgent', 'httpsAgent', 'cancelToken'
+  ], function defaultToInstanceConfig(prop) {
+    config[prop] = typeof instanceConfig[prop] === 'undefined' ? defaults[prop] : instanceConfig[prop];
+  });
+
+  return config;
+};

lib/utils.js

@@ -260,6 +260,32 @@ function merge(/* obj1, obj2, obj3, ... */) {
   return result;
 }
 
+/**
+ * Function equal to merge with the difference being that no reference
+ * to original objects is kept.
+ *
+ * @see merge
+ * @param {Object} obj1 Object to merge
+ * @returns {Object} Result of all merge properties
+ */
+function deepMerge(/* obj1, obj2, obj3, ... */) {
+  var result = {};
+  function assignValue(val, key) {
+    if (typeof result[key] === 'object' && typeof val === 'object') {
+      result[key] = merge(result[key], val);
+    } else if (typeof val === 'object') {
+      result[key] = merge({}, val);
+    } else {
+      result[key] = val;
+    }
+  }
+
+  for (var i = 0, l = arguments.length; i < l; i++) {
+    forEach(arguments[i], assignValue);
+  }
+  return result;
+}
+
 /**
  * Extends object a by mutably adding to it the properties of object b.
  *
@@ -279,43 +305,6 @@ function extend(a, b, thisArg) {
   return a;
 }
 
-
-/**
- * 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
- */
-function mergeConfig(defaults, instanceConfig) {
-  instanceConfig = instanceConfig || {};
-  var config = {};
-  forEach(['url', 'method', 'params', 'data'], function valueFromInstanceConfig(prop) {
-    config[prop] = instanceConfig[prop];
-  });
-  forEach(['headers', 'auth', 'proxy'], function mergeInstanceConfigWithDefaults(prop) {
-    if (!isUndefined(instanceConfig[prop])) {
-      if (isObject(instanceConfig[prop])) {
-        config[prop] = merge(defaults[prop], instanceConfig[prop]);
-      } else {
-        config[prop] = instanceConfig[prop];
-      }
-    } else if (!isUndefined(defaults[prop])) {
-      config[prop] = JSON.parse(JSON.stringify(defaults[prop]));
-    }
-  });
-  forEach([
-    'baseURL', 'transformRequest', 'transformResponse', 'paramsSerializer',
-    'timeout', 'withCredentials', 'adapter', 'responseType', 'xsrfCookieName',
-    'xsrfHeaderName', 'onUploadProgress', 'onDownloadProgress', 'maxContentLength',
-    'validateStatus', 'maxRedirects', 'httpAgent', 'httpsAgent', 'cancelToken'
-  ], function defaultToInstanceConfig(prop) {
-    config[prop] = isUndefined(instanceConfig[prop]) ? defaults[prop] : instanceConfig[prop];
-  });
-  return config;
-}
-
 module.exports = {
   isArray: isArray,
   isArrayBuffer: isArrayBuffer,
@@ -335,7 +324,7 @@ module.exports = {
   isStandardBrowserEnv: isStandardBrowserEnv,
   forEach: forEach,
   merge: merge,
+  deepMerge: deepMerge,
   extend: extend,
-  trim: trim,
-  mergeConfig: mergeConfig
+  trim: trim
 };