Question

我无法在Firestore中的查询中获取应用程序的值。我想用EJS渲染组和apps集合的值，但是从firestore那里的THEN之后，app的值被删除了，之后我就不能使用它们了。

我尝试使用lodash const appsClone = _.cloneDeep(apps);，但没有成功。

apps集合在groups集合内。

以下是我要执行的操作的示例：

let groups = [];  
let apps = [];
const db = admin.firestore();
const group = db.collection('groups').where('roleId', '==', req.session.idRol);
      group.get()   // Trying to get all the groups
      .then(snapshot => {
           snapshot.docs.forEach(grp => {                        
           groups.push(grp.data());  // I can get all the groups without any problem
           grp.ref.collection('apps').get() // once I get the groups I try to get the APPS collection inside every group
           .then(snapshot2 => {
                 snapshot2.docs.forEach(app => {
                    apps.push(app.data()); // I can get the values of app and apps without any problem
                    console.log(apps); // I can get the value here of apps still
                  })
    // Now I cant get the value 
    // And I cant render here because I need the missing groups in the last forEach
            })                        
     });
     console.log("APPS: " + apps);   // Here apps is empty
     res.render("pages/launchpad", { groups, apps }); // Get to render groups but varible apps is empty.
     })
     .catch(err => {
          console.log(err);
     })
     });
     })
     .catch(err => {
        console.log(err);
     })

非常感谢您的帮助，祝您生活愉快。

Answer 1

console.log("APPS: " + apps);在您的诺言兑现之前就已执行。

在致电res.render之前，您应该等待所有诺言都得到解决。这可以通过使用Promise.all

来完成

let groups = [];
let apps = [];
const db = admin.firestore();
const group = db.collection('groups').where('roleId', '==', req.session.idRol);
group.get() // Trying to get all the groups
    .then(snapshot => {
        return Promise.all(snapshot.docs.map(grp => {
            groups.push(grp.data()); // I can get all the groups without any proble
            return grp.ref.collection('apps').get() // once I get the groups I try to get the APPS collection inside every group
                .then(snapshot2 => {
                    snapshot2.docs.forEach(app => {
                        apps.push(app.data()); // I can get the values of app and apps without any problem
                        console.log(apps); // I can get the value here of apps still
                    })

                })
        }))
        .then(() => {
            console.log("APPS: " + apps); 
            res.render("pages/launchpad", {
                groups,
                apps
            });
        })

    })
    .catch(err => {
        console.log(err);
    })
});
})
.catch(err => {
    console.log(err);
})

如何将来自Firestore查询的数据保留在变量中？

1 个答案: