小编Dav*_*ave的帖子

我知道RxJS 5（和其他地方）中的可观察对象是懒惰地执行的。换句话说，直到有订阅者，它们才被执行。但是，我正在尝试预取一些数据。有没有一种方法可以在订阅之前触发可观察对象？

let obs = Rx.Observable.create(observer => {
  console.log('Observer executed');
  // This would actually be fetching data from a server:
  observer.next(42);
});

// Something like obs.warmup() happens here
console.log('Observer is ideally called before this point.');

// Some time later this is called, and hopefully the data is already retrieved.
obs.subscribe(value => {
  console.log('Got ' + value);
});