我正在尝试编写一个在触发Stores/{storeId}/{departmentId}/{productId}时要考虑3个条件的函数，并在ref.child('Home').child('Chiep').child(departmentId).child(productId)中写入新数据。
1）当firestore中没有数据时，我需要通过在2个不同的Realtime DB节点中进行查询来填充firestore中的所有字段：{{1 }}和Stores来拍摄照片。
2）当在Products节点中进行更改且更改来自同一Stores时，我只需要更新一些数据而无需进行任何其他查询。
3）最后，当在{storeId}节点中进行更改并且来自其他Stores的更改时，我只需要在{storeId}节点中进行一个查询。
Stores问题是：查询或不查询另一个exports.homeChiepest = functions.firestore
.document('Stores/{storeId}/{departmentId}/{productId}')
.onWrite((change, context) => {
const storeId = context.params.storeId;
const departmentId = context.params.departmentId;
const productId = context.params.productId;
const ref = admin.database().ref();
// Get an object with the current document value.
// If the document does not exist, it has been deleted.
const document = change.after.exists ? change.after.data() : null;
// Get an object with the previous document value (for update or delete)
const oldDocument = change.before.exists ? change.before.data() : null;
// Prevent infinite loops
if (!change.after.exists) {
console.log('DATA DELETED RETURN NULL');
return null;
}
const newPrice = document.price;
const newTimestamp = document.timestamp;
return ref.child('Home').child('Chiep')
.child(departmentId).child(productId)
.once('value')
.then(dataSnapshot => {
if (dataSnapshot.val() !== null) {
console.log('CHIEP DOES exist');
const oldPrice = dataSnapshot.val().price;
const storeKey = dataSnapshot.val().storeKey;
if (storeId === storeKey) {
console.log('SAME STORE - Change price and timestamp');
var newChiepest = {
timestamp: newTimestamp,
price: newPrice
};
return dataSnapshot.ref.update(newChiepest);
} else {
console.log('OTHER STORE - Verify if price is chieper...');
if (newPrice <= oldPrice) {
console.log('NEW PRICE: '+newPrice+' is chieper than the older one: '+oldPrice);
return change.after.ref.parent.parent.get().then(doc => { // HERE Avoid nesting promises
newStoreImg = doc.data().image;
var newStoreChiep = {
price: newPrice,
storeImg: newStoreImg,
storeKey: storeId,
timestamp: newTimestamp
};
return dataSnapshot.ref.update(newStoreChiep);
});
} else {
console.log('NEW PRICE: '+newPrice+' is mode EXPENSIVE than the older one: '+oldPrice);
}
return null;
}
} else {
console.log('data does NOT exist, so WRITE IT!');
let getStoreData = change.after.ref.parent.parent.get();
let getProductData = admin.firestore().collection('Products').doc('Departments').collection(departmentId).doc(productId).get();
return Promise.all([getStoreData, getProductData]).then(values => { // HERE Avoid nesting promises
const [store, product] = values;
var newHomeChiepest = {
depId: departmentId,
price: newPrice,
prodImg: product.data().image,
prodKey: productId,
storeKey: storeId,
storeImg: store.data().image,
timestamp: newTimestamp
};
return dataSnapshot.ref.set(newHomeChiepest);
});
}
})
.catch(error => {
console.log('Catch error reading Home: ',departmentId ,'/', productId,'; message: ',error);
return false;
});
});
节点的不同可能性使我在上载firestore时出现警告，即：
警告避免嵌套承诺诺言/不嵌套
感谢您对重构此代码的任何帮助。
答案 0 :(得分：1)
您可以使用变量来管理“分流”，具体取决于不同的情况，如下所示（未测试）：
toString()