1
我试图返回一个将返回数据的observable,如下所示。当取消订阅被调用时Observable为空
getRootGroupNodes(): Observable<Group[]> {
return Observable.create(function(observer) {
var groups = [
{ groupName: "Group1" },
{ groupName: "Group2" }
]
observer.next(groups);
observer.complete();
});
}
当我尝试使用它
this._loadGroupsSubscription = this._apiGroupService.getRootGroupNodes()
.retry(3)
.subscribe(
groups => {
// do somethign with groups
},
err => { this._log.logMessage("failed to retrieve groups"); },
() => {
this._loadGroupsSubscription.unsubscribe();
}
);
我得到this._loadGroupsSubscription
是null
。因此,试图在undefined上调用unsubscribe时会引发异常。任何想法我做错了什么?这应该是基本的..