fix(xhr): should invoke xhr task after onload is triggered (#1055)

Author: JiaLiPassion

lib/browser/browser.ts

@@ -144,7 +144,29 @@ Zone.__load_patch('XHR', (global: any, Zone: ZoneType) => {
 // sometimes on some browsers XMLHttpRequest will fire onreadystatechange with
 // readyState=4 multiple times, so we need to check task state here
 if(!data.aborted&&(XMLHttpRequestasany)[XHR_SCHEDULED]&&task.state===SCHEDULED){
-task.invoke();
+// check whether the xhr has registered onload listener
+// if that is the case, the task should invoke after all
+// onload listeners finish.
+constloadTasks=target['__zone_symbol__loadfalse'];
+if(loadTasks&&loadTasks.length>0){
+constoriInvoke=task.invoke;
+task.invoke=function(){
+// need to load the tasks again, because in other
+// load listener, they may remove themselves
+constloadTasks=target['__zone_symbol__loadfalse'];
+for(leti=0;i<loadTasks.length;i++){
+if(loadTasks[i]===task){
+loadTasks.splice(i,1);
+}
+}
+if(!data.aborted&&task.state===SCHEDULED){
+oriInvoke.call(task);
+}
+};
+loadTasks.push(task);
+}else{
+task.invoke();
+}
 }
 }
 };

test/browser/XMLHttpRequest.spec.ts

@@ -17,23 +17,37 @@ describe('XMLHttpRequest', function() {
 
 it('should intercept XHRs and treat them as MacroTasks',function(done){
 letreq: XMLHttpRequest;
-consttestZoneWithWtf=
-Zone.current.fork((Zoneasany)['wtfZoneSpec']).fork({name: 'TestZone'});
+letonStable: any;
+consttestZoneWithWtf=Zone.current.fork((Zoneasany)['wtfZoneSpec']).fork({
+name: 'TestZone',
+onHasTask: (delegate: ZoneDelegate,curr: Zone,target: Zone,hasTask: HasTaskState)=>{
+if(!hasTask.macroTask){
+onStable&&onStable();
+}
+}
+});
 
 testZoneWithWtf.run(()=>{
 req=newXMLHttpRequest();
+constlogs: string[]=[];
 req.onload=()=>{
-// The last entry in the log should be the invocation for the current onload,
-// which will vary depending on browser environment. The prior entries
-// should be the invocation of the send macrotask.
-expect(wtfMock.log[wtfMock.log.length-3])
-.toEqual('> Zone:invokeTask:XMLHttpRequest.send("<root>::ProxyZone::WTF::TestZone")');
+logs.push('onload');
+};
+onStable=function(){
 expect(wtfMock.log[wtfMock.log.length-2])
+.toEqual('> Zone:invokeTask:XMLHttpRequest.send("<root>::ProxyZone::WTF::TestZone")');
+expect(wtfMock.log[wtfMock.log.length-1])
 .toEqual('< Zone:invokeTask:XMLHttpRequest.send');
 if(supportPatchXHROnProperty()){
-expect(wtfMock.log[wtfMock.log.length-1])
+expect(wtfMock.log[wtfMock.log.length-3])
+.toMatch(/\<Zone\:invokeTask.*addEventListener\:load/);
+expect(wtfMock.log[wtfMock.log.length-4])
 .toMatch(/\>Zone\:invokeTask.*addEventListener\:load/);
 }
+// if browser can patch onload
+if((reqasany)['__zone_symbol__loadfalse']){
+expect(logs).toEqual(['onload']);
+}
 done();
 };