fix(xhr): fix #1072, should set scheduled flag to target

Author: JiaLiPassion

Diff for: lib/browser/browser.ts

@@ -96,6 +96,7 @@ Zone.__load_patch('XHR', (global: any, Zone: ZoneType) => {
   const XHR_LISTENER = zoneSymbol('xhrListener');
   const XHR_SCHEDULED = zoneSymbol('xhrScheduled');
   const XHR_URL = zoneSymbol('xhrURL');
+  const XHR_ERROR_BEFORE_SCHEDULED = zoneSymbol('xhrErrorBeforeScheduled');
 
   interface XHROptions extends TaskData {
     target: any;
@@ -126,9 +127,10 @@ Zone.__load_patch('XHR', (global: any, Zone: ZoneType) => {
     const SCHEDULED = 'scheduled';
 
     function scheduleTask(task: Task) {
-      (XMLHttpRequest as any)[XHR_SCHEDULED] = false;
       const data = <XHROptions>task.data;
       const target = data.target;
+      target[XHR_SCHEDULED] = false;
+      target[XHR_ERROR_BEFORE_SCHEDULED] = false;
       // remove existing event listener
       const listener = target[XHR_LISTENER];
       if (!oriAddListener) {
@@ -143,8 +145,11 @@ Zone.__load_patch('XHR', (global: any, Zone: ZoneType) => {
         if (target.readyState === target.DONE) {
           // sometimes on some browsers XMLHttpRequest will fire onreadystatechange with
           // readyState=4 multiple times, so we need to check task state here
-          if (!data.aborted && (XMLHttpRequest as any)[XHR_SCHEDULED] && task.state === SCHEDULED) {
+          if (!data.aborted && target[XHR_SCHEDULED] && task.state === SCHEDULED) {
             task.invoke();
+          } else if (!data.aborted && target[XHR_SCHEDULED] === false) {
+            // error occurs when xhr.send()
+            target[XHR_ERROR_BEFORE_SCHEDULED] = true;
           }
         }
       };
@@ -155,7 +160,7 @@ Zone.__load_patch('XHR', (global: any, Zone: ZoneType) => {
         target[XHR_TASK] = task;
       }
       sendNative.apply(target, data.args);
-      (XMLHttpRequest as any)[XHR_SCHEDULED] = true;
+      target[XHR_SCHEDULED] = true;
       return task;
     }
 
@@ -191,8 +196,15 @@ Zone.__load_patch('XHR', (global: any, Zone: ZoneType) => {
               args: args,
               aborted: false
             };
-            return scheduleMacroTaskWithCurrentZone(
+            const task = scheduleMacroTaskWithCurrentZone(
                 XMLHTTPREQUEST_SOURCE, placeholderCallback, options, scheduleTask, clearTask);
+            if (self && self[XHR_ERROR_BEFORE_SCHEDULED] === true && !options.aborted &&
+                task.state === SCHEDULED) {
+              // xhr request throw error when send
+              // we should invoke task instead of leaving a scheduled
+              // pending macroTask
+              task.invoke();
+            }
           }
         });
 

Diff for: test/browser/XMLHttpRequest.spec.ts

@@ -251,6 +251,79 @@ describe('XMLHttpRequest', function() {
        });
      });
 
+  it('should trigger readystatechange if xhr request trigger cors error', (done) => {
+    const req = new XMLHttpRequest();
+    let err: any = null;
+    try {
+      req.open('get', 'file:///test', true);
+    } catch (err) {
+      // in IE, open will throw Access is denied error
+      done();
+      return;
+    }
+    req.addEventListener('readystatechange', function(ev) {
+      if (req.readyState === 4) {
+        const xhrScheduled = (req as any)['__zone_symbol__xhrScheduled'];
+        const task = (req as any)['__zone_symbol__xhrTask'];
+        if (xhrScheduled === false) {
+          expect(task.state).toEqual('scheduling');
+          setTimeout(() => {
+            if (err) {
+              expect(task.state).toEqual('unknown');
+            } else {
+              expect(task.state).toEqual('notScheduled');
+            }
+            done();
+          });
+        } else {
+          expect(task.state).toEqual('scheduled');
+          done();
+        }
+      }
+    });
+    try {
+      req.send();
+    } catch (error) {
+      err = error;
+    }
+  });
+
+  it('should invoke task if xhr request trigger cors error', (done) => {
+    const logs: string[] = [];
+    const zone = Zone.current.fork({
+      name: 'xhr',
+      onHasTask: (delegate: ZoneDelegate, curr: Zone, target: Zone, hasTask: HasTaskState) => {
+        logs.push(JSON.stringify(hasTask));
+      }
+    });
+    const req = new XMLHttpRequest();
+    try {
+      req.open('get', 'file:///test', true);
+    } catch (err) {
+      // in IE, open will throw Access is denied error
+      done();
+      return;
+    }
+    zone.run(() => {
+      let isError = false;
+      let timerId = null;
+      try {
+        timerId = (window as any)['__zone_symbol__setTimeout'](() => {
+          expect(logs).toEqual([
+            `{"microTask":false,"macroTask":true,"eventTask":false,"change":"macroTask"}`,
+            `{"microTask":false,"macroTask":false,"eventTask":false,"change":"macroTask"}`
+          ]);
+          done();
+        }, 500);
+        req.send();
+      } catch (error) {
+        isError = true;
+        (window as any)['__zone_symbol__clearTimeout'](timerId);
+        done();
+      }
+    });
+  });
+
   it('should not throw error when get XMLHttpRequest.prototype.onreadystatechange the first time',
      function() {
        const func = function() {