(#3885) - Service worker & fetch() fixes

Changes I needed while writing
https://gist.github.com/marten-de-vries/3bfaf635f9efdbcf5102

Author: marten-de-vries

lib/adapters/http/http.js

@@ -3,7 +3,7 @@
 var CHANGES_BATCH_SIZE = 25;
 
 // according to http://stackoverflow.com/a/417184/680742,
-// the de factor URL length limit is 2000 characters.
+// the de facto URL length limit is 2000 characters.
 // but since most of our measurements don't take the full
 // URL into account, we fudge it a bit.
 // TODO: we could measure the full URL to enforce exactly 2000 chars
@@ -597,7 +597,7 @@ function HttpPouch(opts, callback) {
   }));
 
   // Add the document given by doc (in JSON string format) to the database
-  // given by host. This does not assume that doc is a new document 
+  // given by host. This does not assume that doc is a new document
   // (i.e. does not have a _id or a _rev field.)
   api.post = utils.adapterFun('post', function (doc, opts, callback) {
     // If no options were given, set the callback to be the second parameter
@@ -1030,7 +1030,7 @@ function HttpPouch(opts, callback) {
       source.close();
       utils.call(opts.complete, err);
     }
-    
+
   };
 
   api._useSSE = false;

lib/deps/request-browser.js

@@ -20,23 +20,21 @@ function wrappedFetch() {
     args[i] = arguments[i];
   }
 
-  wrappedPromise.then = promise.then.bind(promise);
-  wrappedPromise.catch = promise.catch.bind(promise);
   wrappedPromise.promise = promise;
 
-  fetch.apply(null, args).then(function(response) {
+  utils.Promise.resolve().then(function () {
+    return fetch.apply(null, args);
+  }).then(function(response) {
     wrappedPromise.resolve(response);
-  }, function(error) {
-    wrappedPromise.reject(error);
   }).catch(function(error) {
-    wrappedPromise.catch(error);
+    wrappedPromise.reject(error);
   });
 
   return wrappedPromise;
 }
 
 function fetchRequest(options, callback) {
-  var wrappedPromise, timer, fetchResponse;
+  var wrappedPromise, timer, response;
 
   var headers = new Headers();
 
@@ -81,28 +79,28 @@ function fetchRequest(options, callback) {
     }, options.timeout);
   }
 
-  wrappedPromise.promise.then(function(response) {
-    var result;
-
-    fetchResponse = response;
+  wrappedPromise.promise.then(function(fetchResponse) {
+    response = {
+      statusCode: fetchResponse.status
+    };
 
     if (options.timeout > 0) {
       clearTimeout(timer);
     }
 
-    if (response.status >= 200 && response.status < 300) {
-      return options.binary ? response.blob() : response.text();
+    if (response.statusCode >= 200 && response.statusCode < 300) {
+      return options.binary ? fetchResponse.blob() : fetchResponse.text();
     }
 
-    return result.json();
+    return fetchResponse.json();
   }).then(function(result) {
-    if (fetchResponse.status >= 200 && fetchResponse.status < 300) {
-      callback(null, fetchResponse, result);
+    if (response.statusCode >= 200 && response.statusCode < 300) {
+      callback(null, response, result);
     } else {
-      callback(result, fetchResponse);
+      callback(result, response);
     }
   }).catch(function(error) {
-    callback(error, fetchResponse);
+    callback(error, response);
   });
 
   return {abort: wrappedPromise.reject};
@@ -214,10 +212,21 @@ function xhRequest(options, callback) {
   return {abort: abortReq};
 }
 
+function testXhr() {
+  try {
+    new XMLHttpRequest();
+    return true;
+  } catch (err) {
+    return false;
+  }
+}
+
+var hasXhr = testXhr();
+
 module.exports = function(options, callback) {
-  if (typeof XMLHttpRequest === 'undefined' && !options.xhr) {
-    return fetchRequest(options, callback);
-  } else {
+  if (hasXhr || options.xhr) {
     return xhRequest(options, callback);
+  } else {
+    return fetchRequest(options, callback);
   }
 };