如何在不检索父节点的情况下检查密钥是否存在？ [Firebase /数据库]

Question

I want to check if a key exists in the Realtime database. I know that I can retrieve the parent not and then use .hasChild('theKey') to check for it, but the parent node might be massive and loading all of it might be expensive.

I also know that I can only ask for the key from the Realtime DB, and if it does not exist, it will throw an error. But this method is not so good for me either because I don't know how to make sure that the thrown error is because that the key does not exist, not, for example, a network problem or something else.

And by the way, I am using node.js in Firebase Functions for accessing the DB.

Answer 1

You can use the shallow parameter for checking if a key exists. If data exists, it will return either the value (for primitives) or 'true' (for objects) and if it doesn't exist, it will return null .

Read more: https://firebase.google.com/docs/database/rest/retrieve-data#shallow