前端希望能以文字顯示現在上傳的進度
如:

上傳的部分是沒有問題的，獲取進度的程式碼在主控台也是沒問題的

this.progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;           
console.log("Upload is " + this.progress + "% done");

整段上傳的程式碼

  uploadTask.on(
    "state_changed",
    function(snapshot) {
     this.progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;           
      console.log("Upload is " + this.progress + "% done");
      switch (snapshot.state) {
       case firebase.storage.TaskState.PAUSED: // or 'paused'
         console.log("Upload is paused");
         break;
       case firebase.storage.TaskState.RUNNING: // or 'running'
          console.log("Upload is running");
          break;
            }
          },
        );

前端的程式碼

上傳進度 : {{progress}} %

progress一開始就設為 0

  data() {
    return {
      progress: 0,
    };

但我的畫面永遠顯示

上傳進度 : 0 %

前端畫面並沒有隨著資料更新，想請問是哪邊出問題?