Improve error handling

lib/adapters/http.js

@@ -12,6 +12,8 @@ var url = require('url');
 var zlib = require('zlib');
 var pkg = require('./../../package.json');
 var Buffer = require('buffer').Buffer;
+var createError = require('../core/createError');
+var enhanceError = require('../core/enhanceError');
 
 /*eslint consistent-return:0*/
 module.exports = function httpAdapter(resolve, reject, config) {
@@ -33,7 +35,10 @@ module.exports = function httpAdapter(resolve, reject, config) {
     } else if (utils.isString(data)) {
       data = new Buffer(data, 'utf-8');
     } else {
-      return reject(new Error('Data after transformation must be a string, an ArrayBuffer, or a Stream'));
+      return reject(createError(
+        'Data after transformation must be a string, an ArrayBuffer, or a Stream',
+        config
+      ));
     }
 
     // Add Content-Length header if data exists
@@ -122,13 +127,13 @@ module.exports = function httpAdapter(resolve, reject, config) {
 
         // make sure the content length is not over the maxContentLength if specified
         if (config.maxContentLength > -1 && Buffer.concat(responseBuffer).length > config.maxContentLength) {
-          reject(new Error('maxContentLength size of ' + config.maxContentLength + ' exceeded'));
+          reject(createError('maxContentLength size of ' + config.maxContentLength + ' exceeded', config));
         }
       });
 
       stream.on('error', function handleStreamError(err) {
         if (aborted) return;
-        reject(err);
+        reject(enhanceError(err, config));
       });
 
       stream.on('end', function handleStreamEnd() {
@@ -145,17 +150,14 @@ module.exports = function httpAdapter(resolve, reject, config) {
   // Handle errors
   req.on('error', function handleRequestError(err) {
     if (aborted) return;
-    reject(err);
+    reject(enhanceError(err, config));
   });
 
   // Handle request timeout
   if (config.timeout && !timer) {
     timer = setTimeout(function handleRequestTimeout() {
-      var err = new Error('timeout of ' + config.timeout + 'ms exceeded');
-      err.timeout = config.timeout;
-      err.code = 'ECONNABORTED';
       req.abort();
-      reject(err);
+      reject(createError('timeout of ' + config.timeout + 'ms exceeded', config, 'ECONNABORTED'));
       aborted = true;
     }, config.timeout);
   }

lib/adapters/xhr.js

@@ -6,6 +6,7 @@ var transformData = require('./../core/transformData');
 var buildURL = require('./../helpers/buildURL');
 var parseHeaders = require('./../helpers/parseHeaders');
 var isURLSameOrigin = require('./../helpers/isURLSameOrigin');
+var createError = require('../core/createError');
 var btoa = (typeof window !== 'undefined' && window.btoa) || require('./../helpers/btoa');
 
 module.exports = function xhrAdapter(resolve, reject, config) {
@@ -82,7 +83,7 @@ module.exports = function xhrAdapter(resolve, reject, config) {
   request.onerror = function handleError() {
     // Real errors are hidden from us by the browser
     // onerror should only fire if it's a network error
-    reject(new Error('Network Error'));
+    reject(createError('Network Error', config));
 
     // Clean up request
     request = null;
@@ -90,10 +91,7 @@ module.exports = function xhrAdapter(resolve, reject, config) {
 
   // Handle timeout
   request.ontimeout = function handleTimeout() {
-    var err = new Error('timeout of ' + config.timeout + 'ms exceeded');
-    err.timeout = config.timeout;
-    err.code = 'ECONNABORTED';
-    reject(err);
+    reject(createError('timeout of ' + config.timeout + 'ms exceeded', config, 'ECONNABORTED'));
 
     // Clean up request
     request = null;

lib/core/createError.js

@@ -0,0 +1,16 @@
+'use strict';
+
+var enhanceError = require('./enhanceError');
+
+/**
+ * Create an Error with the specified message, config, and optional error code.
+ *
+ * @param {string} message The error message.
+ * @param {Object} config The config object.
+ * @param {string} [code] The error code (for example, 'ECONNABORTED').
+ * @returns {Error} The created error.
+ */
+module.exports = function createError(message, config, code) {
+  var error = new Error(message);
+  return enhanceError(error, config, code);
+};

lib/core/enhanceError.js

@@ -0,0 +1,17 @@
+'use strict';
+
+/**
+ * Update an Error with the specified config and optional error code.
+ *
+ * @param {Error} error The error to update.
+ * @param {Object} config The config object.
+ * @param {string} [code] The error code (for example, 'ECONNABORTED').
+ * @returns {Error} The error.
+ */
+module.exports = function enhanceError(error, config, code) {
+  error.config = config;
+  if (code) {
+    error.code = code;
+  }
+  return error;
+};

lib/core/settle.js

@@ -1,5 +1,7 @@
 'use strict';
 
+var createError = require('./createError');
+
 /**
  * Resolve or reject a Promise based on response status.
  *
@@ -13,6 +15,8 @@ module.exports = function settle(resolve, reject, response) {
   if (!response.status || !validateStatus || validateStatus(response.status)) {
     resolve(response);
   } else {
-    reject(response);
+    var error = createError('Request failed with status code ' + response.status, response.config);
+    error.response = response;
+    reject(error);
   }
 };