Refactor mergeConfig without utils.deepMerge (#2844)

* Adding failing test

* Fixing #2587 default custom config persisting

* Adding Concat keys and filter duplicates

* Fixed value from CPE

* update for review feedbacks

* no deepMerge

* only merge between plain objects

* fix rename

* always merge config by mergeConfig

* extract function mergeDeepProperties

* refactor mergeConfig with all keys, and add special logic for validateStatus

* add test for resetting headers

* add lots of tests and fix a bug

* should not inherit `data`

* use simple toString

* revert #1845

Co-authored-by: David Tanner <david.tanner@lifeomic.com>
Co-authored-by: Justin Beckwith <justin.beckwith@gmail.com>

lib/core/Axios.js

@@ -73,7 +73,7 @@ Axios.prototype.getUri = function getUri(config) {
 utils.forEach(['delete', 'get', 'head', 'options'], function forEachMethodNoData(method) {
   /*eslint func-names:0*/
   Axios.prototype[method] = function(url, config) {
-    return this.request(utils.merge(config || {}, {
+    return this.request(mergeConfig(config || {}, {
       method: method,
       url: url
     }));
@@ -83,7 +83,7 @@ utils.forEach(['delete', 'get', 'head', 'options'], function forEachMethodNoData
 utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
   /*eslint func-names:0*/
   Axios.prototype[method] = function(url, data, config) {
-    return this.request(utils.merge(config || {}, {
+    return this.request(mergeConfig(config || {}, {
       method: method,
       url: url,
       data: data

lib/core/dispatchRequest.js

@@ -47,13 +47,6 @@ module.exports = function dispatchRequest(config) {
     }
   );
 
-  // Remove header where value is null
-  utils.forEach(config.headers, function deleteNullValueHeaders(value, key) {
-    if (value === null) {
-      delete config.headers[key];
-    }
-  });
-
   var adapter = config.adapter || defaults.adapter;
 
   return adapter(config).then(function onAdapterResolution(response) {

lib/core/mergeConfig.js

@@ -18,56 +18,70 @@ module.exports = function mergeConfig(config1, config2) {
   var valueFromConfig2Keys = ['url', 'method', 'data'];
   var mergeDeepPropertiesKeys = ['headers', 'auth', 'proxy', 'params'];
   var defaultToConfig2Keys = [
-    'baseURL', 'url', 'transformRequest', 'transformResponse', 'paramsSerializer',
-    'timeout', 'withCredentials', 'adapter', 'responseType', 'xsrfCookieName',
-    'xsrfHeaderName', 'onUploadProgress', 'onDownloadProgress',
-    'maxContentLength', 'maxBodyLength', 'validateStatus', 'maxRedirects', 'httpAgent',
+    'baseURL', 'transformRequest', 'transformResponse', 'paramsSerializer',
+    'timeout', 'timeoutMessage', 'withCredentials', 'adapter', 'responseType', 'xsrfCookieName',
+    'xsrfHeaderName', 'onUploadProgress', 'onDownloadProgress', 'decompress',
+    'maxContentLength', 'maxBodyLength', 'maxRedirects', 'transport', 'httpAgent',
     'httpsAgent', 'cancelToken', 'socketPath', 'responseEncoding'
   ];
+  var directMergeKeys = ['validateStatus'];
+
+  function getMergedValue(target, source) {
+    if (utils.isPlainObject(target) && utils.isPlainObject(source)) {
+      return utils.merge(target, source);
+    } else if (utils.isPlainObject(source)) {
+      return utils.merge({}, source);
+    } else if (utils.isArray(source)) {
+      return source.slice();
+    }
+    return source;
+  }
+
+  function mergeDeepProperties(prop) {
+    if (!utils.isUndefined(config2[prop])) {
+      config[prop] = getMergedValue(config1[prop], config2[prop]);
+    } else if (!utils.isUndefined(config1[prop])) {
+      config[prop] = getMergedValue(undefined, config1[prop]);
+    }
+  }
 
   utils.forEach(valueFromConfig2Keys, function valueFromConfig2(prop) {
-    if (typeof config2[prop] !== 'undefined') {
-      config[prop] = config2[prop];
+    if (!utils.isUndefined(config2[prop])) {
+      config[prop] = getMergedValue(undefined, config2[prop]);
     }
   });
 
-  utils.forEach(mergeDeepPropertiesKeys, function mergeDeepProperties(prop) {
-    if (utils.isObject(config2[prop])) {
-      config[prop] = utils.deepMerge(config1[prop], config2[prop]);
-    } else if (typeof config2[prop] !== 'undefined') {
-      config[prop] = config2[prop];
-    } else if (utils.isObject(config1[prop])) {
-      config[prop] = utils.deepMerge(config1[prop]);
-    } else if (typeof config1[prop] !== 'undefined') {
-      config[prop] = config1[prop];
-    }
-  });
+  utils.forEach(mergeDeepPropertiesKeys, mergeDeepProperties);
 
   utils.forEach(defaultToConfig2Keys, function defaultToConfig2(prop) {
-    if (typeof config2[prop] !== 'undefined') {
-      config[prop] = config2[prop];
-    } else if (typeof config1[prop] !== 'undefined') {
-      config[prop] = config1[prop];
+    if (!utils.isUndefined(config2[prop])) {
+      config[prop] = getMergedValue(undefined, config2[prop]);
+    } else if (!utils.isUndefined(config1[prop])) {
+      config[prop] = getMergedValue(undefined, config1[prop]);
+    }
+  });
+
+  utils.forEach(directMergeKeys, function merge(prop) {
+    if (prop in config2) {
+      config[prop] = getMergedValue(config1[prop], config2[prop]);
+    } else if (prop in config1) {
+      config[prop] = getMergedValue(undefined, config1[prop]);
     }
   });
 
   var axiosKeys = valueFromConfig2Keys
     .concat(mergeDeepPropertiesKeys)
-    .concat(defaultToConfig2Keys);
+    .concat(defaultToConfig2Keys)
+    .concat(directMergeKeys);
 
   var otherKeys = Object
-    .keys(config2)
+    .keys(config1)
+    .concat(Object.keys(config2))
     .filter(function filterAxiosKeys(key) {
       return axiosKeys.indexOf(key) === -1;
     });
 
-  utils.forEach(otherKeys, function otherKeysDefaultToConfig2(prop) {
-    if (typeof config2[prop] !== 'undefined') {
-      config[prop] = config2[prop];
-    } else if (typeof config1[prop] !== 'undefined') {
-      config[prop] = config1[prop];
-    }
-  });
+  utils.forEach(otherKeys, mergeDeepProperties);
 
   return config;
 };

lib/utils.js

@@ -105,6 +105,21 @@ function isObject(val) {
   return val !== null && typeof val === 'object';
 }
 
+/**
+ * Determine if a value is a plain Object
+ *
+ * @param {Object} val The value to test
+ * @return {boolean} True if value is a plain Object, otherwise false
+ */
+function isPlainObject(val) {
+  if (toString.call(val) !== '[object Object]') {
+    return false;
+  }
+
+  var prototype = Object.getPrototypeOf(val);
+  return prototype === null || prototype === Object.prototype;
+}
+
 /**
  * Determine if a value is a Date
  *
@@ -261,8 +276,12 @@ function forEach(obj, fn) {
 function merge(/* obj1, obj2, obj3, ... */) {
   var result = {};
   function assignValue(val, key) {
-    if (typeof result[key] === 'object' && typeof val === 'object') {
+    if (isPlainObject(result[key]) && isPlainObject(val)) {
       result[key] = merge(result[key], val);
+    } else if (isPlainObject(val)) {
+      result[key] = merge({}, val);
+    } else if (isArray(val)) {
+      result[key] = val.slice();
     } else {
       result[key] = val;
     }
@@ -274,37 +293,6 @@ 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] = deepMerge(result[key], val);
-    } else if (typeof val === 'object') {
-      result[key] = deepMerge({}, val);
-    } else {
-      result[key] = val;
-    }
-  }
-
-  var lastArgument = arguments[arguments.length - 1];
-  if (lastArgument === null || typeof lastArgument === 'undefined') {
-    return lastArgument;
-  }
-
-  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.
  *
@@ -333,6 +321,7 @@ module.exports = {
   isString: isString,
   isNumber: isNumber,
   isObject: isObject,
+  isPlainObject: isPlainObject,
   isUndefined: isUndefined,
   isDate: isDate,
   isFile: isFile,
@@ -343,7 +332,6 @@ module.exports = {
   isStandardBrowserEnv: isStandardBrowserEnv,
   forEach: forEach,
   merge: merge,
-  deepMerge: deepMerge,
   extend: extend,
   trim: trim
 };