即使if(doc.exists)工作完美，但如果我點擊的特定字母沒有數據，它不會顯示控制臺消息 -console.log("There is a no song which starting with clickedletter");例如 - 如果我單擊按鈕“A”并成像有一首以字母“A”開頭的歌曲。此數據很快彈出，但是當我單擊 firestore 文檔中不存在數據的按鈕“T”時，控制臺消息未顯示。function getID(a){    console.log("youclicked", a.id);    var id = a.id;    //getting this "a" value from an alphabetic pagination bar----------    const clickedletter = a.getAttribute('value');    var Aristid = sessionStorage.getItem("getArtistID");    console.log("current artist ID "+ searchforid);    db.collectionGroup('MP3_Songs').where("Idofartist", "==", Aristid).orderBy("Song_name").startAt(clickedletter).endAt(clickedletter +'\uf88ff').get().then((documentSnapshot) =>{          documentSnapshot.forEach(doc=> {            if(doc.exists){                              const data = doc.data();              console.log("start with clickedletter", data);              gotdata.innerText = "Song name: " + data.Song_name;            } else{             // this is the problem I got. This console log does not show if there is no data.---                console.log("There is a no song which starting with clickedletter");            }                  })                          }).catch(function(error) {          console.log("Error getting document:", error);      });}