Fixes Fetch error when debugging in Chrome

Summary:
Fixes https://github.com/facebook/react-native/issues/6679
Closes https://github.com/facebook/react-native/pull/8512

Differential Revision: D3503958

Pulled By: davidaurelio

fbshipit-source-id: 204eaa40832c9acb455f736d0cae40385c67a82f

Libraries/Fetch/fetch.js

@@ -8,6 +8,8 @@
  *
  * This is a third-party polyfill grabbed from:
  * https://github.com/github/fetch
+ * copied from v1.0.0
+ * https://github.com/github/fetch/commit/4bde61788365cfd3d6155eee8aed3c7673d299d5
  *
  * @providesModule fetch
  * @nolint
@@ -48,6 +50,21 @@ var self = {};
     return
   }
 
+  var support = {
+    searchParams: 'URLSearchParams' in self,
+    iterable: 'Symbol' in self && 'iterator' in Symbol,
+    blob: 'FileReader' in self && 'Blob' in self && (function() {
+      try {
+        new Blob()
+        return true
+      } catch(e) {
+        return false
+      }
+    })(),
+    formData: 'FormData' in self,
+    arrayBuffer: 'ArrayBuffer' in self
+  }
+
   function normalizeName(name) {
     if (typeof name !== 'string') {
       name = String(name)
@@ -65,6 +82,24 @@ var self = {};
     return value
   }
 
+  // Build a destructive iterator for the value list
+  function iteratorFor(items) {
+    var iterator = {
+      next: function() {
+        var value = items.shift()
+        return {done: value === undefined, value: value}
+      }
+    }
+
+    if (support.iterable) {
+      iterator[Symbol.iterator] = function() {
+        return iterator
+      }
+    }
+
+    return iterator
+  }
+
   function Headers(headers) {
     this.map = {}
 
@@ -120,6 +155,28 @@ var self = {};
     }, this)
   }
 
+  Headers.prototype.keys = function() {
+    var items = []
+    this.forEach(function(value, name) { items.push(name) })
+    return iteratorFor(items)
+  }
+
+  Headers.prototype.values = function() {
+    var items = []
+    this.forEach(function(value) { items.push(value) })
+    return iteratorFor(items)
+  }
+
+  Headers.prototype.entries = function() {
+    var items = []
+    this.forEach(function(value, name) { items.push([name, value]) })
+    return iteratorFor(items)
+  }
+
+  if (support.iterable) {
+    Headers.prototype[Symbol.iterator] = Headers.prototype.entries
+  }
+
   function consumed(body) {
     if (body.bodyUsed) {
       return Promise.reject(new TypeError('Already read'))
@@ -150,19 +207,6 @@ var self = {};
     return fileReaderReady(reader)
   }
 
-  var support = {
-    blob: typeof FileReader === 'function' && typeof Blob === 'function' && (function() {
-      try {
-        new Blob();
-        return true
-      } catch(e) {
-        return false
-      }
-    })(),
-    formData: typeof FormData === 'function',
-    arrayBuffer: typeof ArrayBuffer === 'function'
-  }
-
   function Body() {
     this.bodyUsed = false
 
@@ -174,6 +218,8 @@ var self = {};
         this._bodyBlob = body
       } else if (support.formData && FormData.prototype.isPrototypeOf(body)) {
         this._bodyFormData = body
+      } else if (support.searchParams && URLSearchParams.prototype.isPrototypeOf(body)) {
+        this._bodyText = body.toString()
       } else if (!body) {
         this._bodyText = ''
       } else if (support.arrayBuffer && ArrayBuffer.prototype.isPrototypeOf(body)) {
@@ -188,6 +234,8 @@ var self = {};
           this.headers.set('content-type', 'text/plain;charset=UTF-8')
         } else if (this._bodyBlob && this._bodyBlob.type) {
           this.headers.set('content-type', this._bodyBlob.type)
+        } else if (support.searchParams && URLSearchParams.prototype.isPrototypeOf(body)) {
+          this.headers.set('content-type', 'application/x-www-form-urlencoded;charset=UTF-8')
         }
       }
     }
@@ -309,7 +357,7 @@ var self = {};
 
   function headers(xhr) {
     var head = new Headers()
-    var pairs = xhr.getAllResponseHeaders().trim().split('\n')
+    var pairs = (xhr.getAllResponseHeaders() || '').trim().split('\n')
     pairs.forEach(function(header) {
       var split = header.trim().split(':')
       var key = split.shift().trim()
@@ -334,6 +382,7 @@ var self = {};
     this.url = options.url || ''
     this._initBody(bodyInit)
   }
+
   Body.call(Response.prototype)
 
   Response.prototype.clone = function() {
@@ -361,9 +410,9 @@ var self = {};
     return new Response(null, {status: status, headers: {location: url}})
   }
 
-  self.Headers = Headers;
-  self.Request = Request;
-  self.Response = Response;
+  self.Headers = Headers
+  self.Request = Request
+  self.Response = Response
 
   self.fetch = function(input, init) {
     return new Promise(function(resolve, reject) {
@@ -386,23 +435,17 @@ var self = {};
           return xhr.getResponseHeader('X-Request-URL')
         }
 
-        return;
+        return
       }
 
       xhr.onload = function() {
-        var status = (xhr.status === 1223) ? 204 : xhr.status
-        if (status < 100 || status > 599) {
-          reject(new TypeError('Network request failed'))
-          return
-        }
-
         var options = {
-          status: status,
+          status: xhr.status,
           statusText: xhr.statusText,
           headers: headers(xhr),
           url: responseURL()
         }
-        var body = 'response' in xhr ? xhr.response : xhr.responseText;
+        var body = 'response' in xhr ? xhr.response : xhr.responseText
         resolve(new Response(body, options))
       }
 
@@ -410,6 +453,10 @@ var self = {};
         reject(new TypeError('Network request failed'))
       }
 
+      xhr.ontimeout = function() {
+        reject(new TypeError('Network request failed'))
+      }
+
       xhr.open(request.method, request.url, true)
 
       if (request.credentials === 'include') {