javascript - 返回结果作为 Typescript 中的 promise

Question

如何让下面的函数返回一个 promise ，以便我可以在调用该函数的页面中正确处理它？<​​/p>

getUploads() {
    const rootDef = this.db.database.ref();
    const uploadsRef = rootDef.child('userUploads').orderByChild('time');
    const userRef = rootDef.child("userProfile");
    var uploads = [];

    uploadsRef.once("value").then((uploadSnaps) => {

      uploadSnaps.forEach((uploadSnap) => {

        var upload = uploadSnap.val();

        userRef.child(uploadSnap.val().user).once("value").then((userSnap) => {
          upload.displayName = userSnap.val().displayName;
          upload.avatar = userSnap.val().avatar;
          uploads.push(upload);
        });

      });

    });

    return uploads;
}

我尝试了以下方法，但显示错误。应该如何修改？

return new Promise((resolve, reject) => {
  resolve(uploads);
});

我将调用此方法，如下所示。

this.db.getUploads().then((uploads) => {
  this.allUploads = uploads;
  console.log(this.allUploads);
});

Answer 1

我认为您可以将方法的内容括起来

getUploads() {
    return new Promise((resolve, reject) => {
        // content of method
        resolve(uploads); // instead of "return uploads"
    });
}