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Cloud Functions 和 Firestore：使用 Promise.all() 跟踪多个文档修改

[英]Cloud Functions and Firestore: Using Promise.all() to track multiple documetn modifications

原文 2020-09-05 15:28:19 9 1 javascript/ firebase/ google-cloud-firestore/ promise/ google-cloud-functions

I use a callable Cloud function for creating a new user.我使用可调用的 Cloud 函数来创建新用户。 For this user, multiple documents in Cloud Firestore are created.对于此用户，会在 Cloud Firestore 中创建多个文档。

I do not want to store only parts of the data, if one promise (document creation fails), but completely undo the registration, so I use Promise.all(documentCreationPromisses)我不想只存储部分数据，如果一个承诺（文档创建失败），而是完全撤消注册，所以我使用Promise.all(documentCreationPromisses)

So my question is if it is still possible that some documents are created and others are not, although I use Promise.all() ?所以我的问题是，尽管我使用 Promise.all() ，但是否仍有可能创建某些文档而其他文档则没有？

1 个解决方案

Promise.all() returns a promise that tells you if all of the other promises succeeded, or if any one of them failed. Promise.all()返回一个承诺，告诉您所有其他承诺是否成功，或者其中任何一个都失败了。 It can certainly resolve with a partial set of successes, and there was a failure, you would have to check each individual promise to find out which ones succeeded or failed.它当然可以通过部分成功来解决，如果有失败，您必须检查每个承诺以找出哪些成功或失败。

If you are modifying a bunch of documents in Firestore, and you require that all of the modifications either fully succeed, otherwise nothing happens (a full rollback), then you should use a batch write or transaction .如果您正在 Firestore 中修改一堆文档，并且您要求所有修改要么完全成功，否则什么都不会发生（完全回滚），那么您应该使用批量写入或事务。 With a batch writes and transactions, everything must succeed, or the entire batch fails.对于批量写入和事务，一切都必须成功，否则整个批次都会失败。 The single returned promise from that batch will tell you what happened.该批次返回的单个承诺将告诉您发生了什么。