解決未按預期工作的承諾

Question

我想使用 async / await 運行console.log('Procccess Ends'); updateGuider函數解決后..

類似於下面的代碼：

 tutor(); async function tutor(){ console.log('tutor function initiated..'); // wait until updateGuider function resolves await updateGuider('default'); // The expected result is to reach this line after updateGuider resolves, but we can't so far! console.log('Procccess Ends'); } function updateGuider(state){ return new Promise((resolve) => { if(state == 'done'){ console.log('updateGuider has been resolved!'); resolve(); } switch(state) { case 'default': speak(); break; } }); } async function speak(){ setTimeout(function(){ //after 5 seconds we resolve the updateGuider from speak function updateGuider('done') },5000) }

但是即使我們解決了updateGuider它也不會運行console.log('Procccess Ends');

我想念什么以及如何解決這個問題？

我怎樣才能解決updateGuider從speak ？

更新：感謝@h2oooooooo這段代碼有效，但我不明白它是如何工作的，如果這是一個好的解決方案以及它是如何工作的，請幫我一把！

 tutor(); async function tutor(){ console.log('tutor function initiated..'); // wait until updateGuider function resolves await updateGuider('default'); // The expected result is to reach this line after updateGuider resolves, but we can't so far! console.log('Procccess Ends'); } function updateGuider(state){ return new Promise((resolve) => { switch(state) { case 'default': speak(resolve); break; } }); } async function speak(resolve){ setTimeout(function(){ //after 5 seconds we resolve the updateGuider from speak function console.log('entered speak') resolve(); },5000) }

Answer 1

每次調用 updateGuider 時都會返回不同的承諾。 嚴格來說，你不能像這樣解析 updaterGuide。 此外，除非您在 async 函數中等待某些東西，否則它什么都不做，所以目前沒有理由是異步的。 這並不完美，但您已了解問題的要點。

function updateGuider(state){    
  return new Promise((resolve) => { 

    if(state == 'done'){
       console.log('updateGuider has been resolved!');
       resolve();    
    }

    switch(state) {
          case 'default':
          speak(resolve);
          break;         
    }

    });  
}

function speak(resolve){

   setTimeout(function(){
      //after 5 seconds we resolve the updateGuider from speak function
      resolve()    
   },5000)

}