角4.2.4 +打字稿2.3.4 + RxJS 5.4.2： 「第一個（）」 不是一個可觀察到的已知

Question

edit See Ikhtiyor's answer as it may fix the TypeScript related issue. My problem came from the fact I forgot to .subscribe and wrote the handler function in .first() directly.

所以，面對這個錯誤（！？！）：

Property 'first' does not exist on type Observable<{}> 

我發現人們堅持以下幾個版本，並修復了以下問題：

Angular 4.2.4 + Typescript 2.3.4 + RxJS 5.4.2

不過，它不適用於我。測試2臺機器（一臺Mac，一臺窗戶）。甚至在清除node_modules和re-npm安裝它們之後都沒有。 任何人都面臨這個阻滯劑？

例子：

const obs = new Observable(observer => { 

    setTimeout(() => { 
    observer.next(
     [{ 
     type: 'voting', 
     title: 'First dynamic resolution', 
     description: 'Issued by dummy web API. Dynamic data rocks.', 
     documents: ['a doc'], 
     voting:{ 'jem': -1 }, 
     status: 'PENDING' 
     }, { 
     type: 'voting', 
     title: 'Other dynamic resolution', 
     description: 'Issued by dummy web API. We know Jem is proud.', 
     documents: ['another doc'], 
     voting:{ 'jem': -1 }, 
     status: 'PENDING' 
     }] 
    ); 
    }, 1000); 
}); 

// Compile stops here: Property 'first' does not exist on type Observable<{}> 
// Original mistake: it's "obs.first().subscribe(..." 
obs.first(data => { 
    console.log('data feteched'); 
}); 

Answer 1

你必須導入每個觀察到的方法或操作員這樣

的方法import 'rxjs/add/observable/of'; 操作員import 'rxjs/add/operator/map';