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Version: 2.9.x

Update

This page discusses how update works and its quirks.

We will use updateDoc in the example, but it works the same for batch.update and transaction.update.

There are 3 type safe issues and 1 critical runtime issue in the official Firestore SDK update API.

Unsafe Type​

Figure Showing Unsafe Firestore Update Type

  1. Does not reject excess member.

  2. Accept unknown(excess) member from stale value, resulting in storing unnecessary information in Firestore.

info

Stale value refer to value that is attached to a variable.

Fresh value refer to value that is not attached to a variable.

  1. Accept undefined but undefined is not a valid Firestore value.

Solution To Unsafe Type​

FirelordJS solves all the stated concerns:

FirelordJS Able to Detect Unknown Member In The Stale Value

Note 1: FirelordJS highlight the unknown member of the fresh value.

Note 2: FirelordJS highlight the unknown member of the stale value and print out the unknown member in Typescript error message, the same error message is also shown for the fresh value.

Note 3: Partial But no Undefined. FirelordJS update allows you to skip member while rejecting undefined, stopping undefined from entering database(undefined is not a valid data type).

note

Note 3 is no longer relevant if you enabled exactOptionalPropertyTypes in tsconfig.

Implicit Data Deletion🦤​

info

By default, official SDK update will deletes nested properties(non-top level properties) that are NOT included.

Do You Know What Will Happen After This Code Run?

The value of a, c and e will be updated, meanwhile d will be deleted.

update

We used to think this is a very terrible design because it deletes your data if you do not pay attention.

But apparently it has use cases, so we added transaction.updateNoFlatten, batch.updateNoFlatten, and updateDocNoFlatten for those who needs the original behavior.

Solution to Implicit Data Deletion​

Internally, FirelordJS flatten the data object to top level only object before pass it to official SDK update. Your input is always what you expect in the database, with no extra knowledge and attention required.

danger

If you want to revert to official SDK, please replace all the nested form with dot notation form or else your fields may get deleted due to official SDK behavior.