Javascript Firebase云功能“;函数返回未定义的预期承诺或值“;
我试图在添加新消息时通过Firebase云函数向组中的每个成员发送推送通知。我不习惯使用承诺,需要一些帮助Javascript Firebase云功能“;函数返回未定义的预期承诺或值“;,javascript,firebase,google-cloud-functions,es6-promise,Javascript,Firebase,Google Cloud Functions,Es6 Promise,我试图在添加新消息时通过Firebase云函数向组中的每个成员发送推送通知。我不习惯使用承诺,需要一些帮助 exports.sendPushFromMessage = functions.database.ref('chats/{groupId}/messages/{msgId}').onCreate((snap, context) => { const groupId = context.params.groupId; const users = []; cons
exports.sendPushFromMessage = functions.database.ref('chats/{groupId}/messages/{msgId}').onCreate((snap, context) => {
const groupId = context.params.groupId;
const users = [];
const msgTitle = 'New Message';
const msgBody = snap.val().messageText;
const creator = snap.val().from;
const root = snap.ref.root;
let messages = [];
return root.child(`groups/${groupId}/selected`).once('value', snapshot => {
snapshot.forEach(user => {
root.child(`users/${user.val().uid}`).once('value', spanshot => {
const expoToken = snapshot.val().token;
const userId = snapshot.val().uid;
if (expoToken && (creator !== userId)) {
messages.push({
"to": expoToken,
"title": msgTitle,
"body": msgBody
});
}
})
})
return messages;
}).then(messages => {
return fetch('https://exp.host/--/api/v2/push/send', {
method: "POST",
headers: {
"Accept": "application/json",
"Content-Type": "application/json"
},
body: JSON.stringify(messages)
})
}).catch((e) => console.log(e));
})
在Firebase函数的日志中,我可以看到以下错误:
函数返回了未定义的预期承诺或值
我知道问题可能在于我如何处理承诺。这个问题困扰了我很长一段时间,如果有人能帮助我,那就太棒了
以下是我尝试过的另一种方法:
exports.sendPushFromMessage = functions.database.ref('chats/{groupId}/messages/{msgId}').onCreate((snap, context) => {
const groupId = context.params.groupId;
const users = [];
const msgTitle = 'New Message';
const msgBody = snap.val().messageText;
const creator = snap.val().from;
const root = snap.ref.root;
root.child(`groups/${groupId}/selected`).once('value', snapshot => {
let users = [];
snapshot.forEach(user => {
const uid = user.val().uid;
users.push(uid);
console.log('fotze' + user.val().uid);
})
return Promise.all(users);
})
.then(users => {
let messages = [];
console.log(users);
users.forEach(user => {
console.log('fucking bitch: ' + user.toString());
console.log('bitch!' + user);
root.child(`users/${user}/`).once('value', snapshot => {
const expoToken = snapshot.val().token;
const userId = snapshot.val().uid;
console.log('cunt' + snapshot.val().token);
if (expoToken && (creator !== userId)) {
messages.push({
"to": expoToken,
"title": msgTitle,
"body": msgBody
})
} // if
}); // once
}); //forEach
return Promise.all(messages);
})
.then(messages => {
return fetch('https://exp.host/--/api/v2/push/send', {
method: "POST",
headers: {
"Accept": "application/json",
"Content-Type": "application/json"
},
body: JSON.stringify(messages)
})
}).catch((e) => console.log(e));
})
请以这种方式进行测试:
exports.sendPushFromMessage = functions.database.ref('chats/{groupId}/messages/{msgId}').onCreate((snap, context) => {
const groupId = context.params.groupId;
const users = [];
const msgTitle = 'New Message';
const msgBody = snap.val().messageText;
const creator = snap.val().from;
const root = snap.ref.root;
let messages = [];
const promises = [];
return root.child(`groups/${groupId}/selected`).once('value', snapshot => {
snapshot.forEach(user => {
const promise = root.child(`users/${user.val().uid}`).once('value', snapshot => {
const expoToken = snapshot.val().token;
const userId = snapshot.val().uid;
if (expoToken && (creator !== userId)) {
messages.push({
"to": expoToken,
"title": msgTitle,
"body": msgBody
});
}
});
promises.push(promise);
});
return Promise.all(promises).then(() => {
return sendMessages(messages);
});
});
});
function sendMessages(messages){
return new Promise((resolve, reject) => {
const f = fetch('https://exp.host/--/api/v2/push/send', {
method: "POST",
headers: {
"Accept": "application/json",
"Content-Type": "application/json"
},
body: JSON.stringify(messages)
});
f.on("end", () => {
resolve();
});
});
}
请以这种方式进行测试:
exports.sendPushFromMessage = functions.database.ref('chats/{groupId}/messages/{msgId}').onCreate((snap, context) => {
const groupId = context.params.groupId;
const users = [];
const msgTitle = 'New Message';
const msgBody = snap.val().messageText;
const creator = snap.val().from;
const root = snap.ref.root;
let messages = [];
const promises = [];
return root.child(`groups/${groupId}/selected`).once('value', snapshot => {
snapshot.forEach(user => {
const promise = root.child(`users/${user.val().uid}`).once('value', snapshot => {
const expoToken = snapshot.val().token;
const userId = snapshot.val().uid;
if (expoToken && (creator !== userId)) {
messages.push({
"to": expoToken,
"title": msgTitle,
"body": msgBody
});
}
});
promises.push(promise);
});
return Promise.all(promises).then(() => {
return sendMessages(messages);
});
});
});
function sendMessages(messages){
return new Promise((resolve, reject) => {
const f = fetch('https://exp.host/--/api/v2/push/send', {
method: "POST",
headers: {
"Accept": "application/json",
"Content-Type": "application/json"
},
body: JSON.stringify(messages)
});
f.on("end", () => {
resolve();
});
});
}
你能在fetch函数中共享代码吗?我已经共享了我用于此函数的所有代码。这就是整个fetch函数。您没有注意到对once()的内部调用返回的承诺。因此,我必须在那里做些什么才能使它工作?很抱歉,我对JavaScript的这一部分非常陌生。将承诺收集到一个数组中,然后使用Promise.all()等待它们。这可能不是唯一的问题,但这里肯定出了问题。你能在fetch函数中共享代码吗?我已经共享了我用于此函数的所有代码。这就是整个fetch函数。您没有注意到对once()的内部调用返回的承诺。因此,我必须在那里做些什么才能使它工作?很抱歉,我对JavaScript的这一部分非常陌生。将承诺收集到一个数组中,然后使用Promise.all()等待它们。这可能不是唯一的问题,但这里肯定出了问题。非常感谢您发布此Answare!它正在工作。我真的很感谢你花时间帮助我!您的代码中有一点输入错误,而不是您键入的快照。但是其他一切都很好。很好,修复了错误。非常感谢您发布此Answare!它正在工作。我真的很感谢你花时间帮助我!您的代码中有一点输入错误,而不是您键入的快照。但是其他一切都很好,很好,修正了打字错误