Refactored adapters loader; (#5277)

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

lib/adapters/adapters.js

@@ -0,0 +1,59 @@
+import utils from '../utils.js';
+import httpAdapter from './http.js';
+import xhrAdapter from './xhr.js';
+import AxiosError from "../core/AxiosError.js";
+
+const knownAdapters = {
+  http: httpAdapter,
+  xhr: xhrAdapter
+}
+
+utils.forEach(knownAdapters, (fn, value) => {
+  if(fn) {
+    try {
+      Object.defineProperty(fn, 'name', {value});
+    } catch (e) {
+      // eslint-disable-next-line no-empty
+    }
+    Object.defineProperty(fn, 'adapterName', {value});
+  }
+});
+
+export default {
+  getAdapter: (adapters) => {
+    adapters = utils.isArray(adapters) ? adapters : [adapters];
+
+    const {length} = adapters;
+    let nameOrAdapter;
+    let adapter;
+
+    for (let i = 0; i < length; i++) {
+      nameOrAdapter = adapters[i];
+      if((adapter = utils.isString(nameOrAdapter) ? knownAdapters[nameOrAdapter.toLowerCase()] : nameOrAdapter)) {
+        break;
+      }
+    }
+
+    if (!adapter) {
+      if (adapter === false) {
+        throw new AxiosError(
+          `Adapter ${nameOrAdapter} is not supported by the environment`,
+          'ERR_NOT_SUPPORT'
+        );
+      }
+
+      throw new Error(
+        utils.hasOwnProp(knownAdapters, nameOrAdapter) ?
+          `Adapter '${nameOrAdapter}' is not available in the build` :
+          `Unknown adapter '${nameOrAdapter}'`
+      );
+    }
+
+    if (!utils.isFunction(adapter)) {
+      throw new TypeError('adapter is not a function');
+    }
+
+    return adapter;
+  },
+  adapters: knownAdapters
+}

lib/adapters/http.js

@@ -100,8 +100,10 @@ function setProxy(options, configProxy, location) {
   };
 }
 
+const isHttpAdapterSupported = typeof process !== 'undefined' && utils.kindOf(process) === 'process';
+
 /*eslint consistent-return:0*/
-export default function httpAdapter(config) {
+export default isHttpAdapterSupported && function httpAdapter(config) {
   return new Promise(function dispatchHttpRequest(resolvePromise, rejectPromise) {
     let data = config.data;
     const responseType = config.responseType;

lib/adapters/index.js

@@ -1,33 +0,0 @@
-import utils from '../utils.js';
-import httpAdapter from './http.js';
-import xhrAdapter from './xhr.js';
-
-const adapters = {
-  http: httpAdapter,
-  xhr: xhrAdapter
-}
-
-export default {
-  getAdapter: (nameOrAdapter) => {
-    if(utils.isString(nameOrAdapter)){
-      const adapter = adapters[nameOrAdapter];
-
-      if (!nameOrAdapter) {
-        throw Error(
-          utils.hasOwnProp(nameOrAdapter) ?
-            `Adapter '${nameOrAdapter}' is not available in the build` :
-            `Can not resolve adapter '${nameOrAdapter}'`
-        );
-      }
-
-      return adapter
-    }
-
-    if (!utils.isFunction(nameOrAdapter)) {
-      throw new TypeError('adapter is not a function');
-    }
-
-    return nameOrAdapter;
-  },
-  adapters
-}

lib/adapters/xhr.js

@@ -43,7 +43,9 @@ function progressEventReducer(listener, isDownloadStream) {
   };
 }
 
-export default function xhrAdapter(config) {
+const isXHRAdapterSupported = typeof XMLHttpRequest !== 'undefined';
+
+export default isXHRAdapterSupported && function (config) {
   return new Promise(function dispatchXhrRequest(resolve, reject) {
     let requestData = config.data;
     const requestHeaders = AxiosHeaders.from(config.headers).normalize();

lib/core/dispatchRequest.js

@@ -5,6 +5,7 @@ import isCancel from '../cancel/isCancel.js';
 import defaults from '../defaults/index.js';
 import CanceledError from '../cancel/CanceledError.js';
 import AxiosHeaders from '../core/AxiosHeaders.js';
+import adapters from "../adapters/adapters.js";
 
 /**
  * Throws a `CanceledError` if cancellation has been requested.
@@ -45,7 +46,7 @@ export default function dispatchRequest(config) {
     config.headers.setContentType('application/x-www-form-urlencoded', false);
   }
 
-  const adapter = config.adapter || defaults.adapter;
+  const adapter = adapters.getAdapter(config.adapter || defaults.adapter);
 
   return adapter(config).then(function onAdapterResolution(response) {
     throwIfCancellationRequested(config);

lib/defaults/index.js

@@ -7,30 +7,11 @@ import toFormData from '../helpers/toFormData.js';
 import toURLEncodedForm from '../helpers/toURLEncodedForm.js';
 import platform from '../platform/index.js';
 import formDataToJSON from '../helpers/formDataToJSON.js';
-import adapters from '../adapters/index.js';
 
 const DEFAULT_CONTENT_TYPE = {
   'Content-Type': undefined
 };
 
-/**
- * If the browser has an XMLHttpRequest object, use the XHR adapter, otherwise use the HTTP
- * adapter
- *
- * @returns {Function}
- */
-function getDefaultAdapter() {
-  let adapter;
-  if (typeof XMLHttpRequest !== 'undefined') {
-    // For browsers use XHR adapter
-    adapter = adapters.getAdapter('xhr');
-  } else if (typeof process !== 'undefined' && utils.kindOf(process) === 'process') {
-    // For node use HTTP adapter
-    adapter = adapters.getAdapter('http');
-  }
-  return adapter;
-}
-
 /**
  * It takes a string, tries to parse it, and if it fails, it returns the stringified version
  * of the input
@@ -60,7 +41,7 @@ const defaults = {
 
   transitional: transitionalDefaults,
 
-  adapter: getDefaultAdapter(),
+  adapter: ['xhr', 'http'],
 
   transformRequest: [function transformRequest(data, headers) {
     const contentType = headers.getContentType() || '';