Qn: In memory database for react-native

[bsr203]

Hi,

I tried to use lokijs to run my test / storybook with sample data. Do you see issues using this adapter on react-native env. I currently get

error: bundling failed: Error: Unable to resolve module `fs` from `/Users/bsr/myApp/node_modules/lokijs/src/lokijs.js`: Module `fs` does not exist in the Haste module map

[radex]

You'd probably need to mock fs so that there's no bundler error, and also tweak the adapter initializer code so that you can use an in-memory database.

But you could also tweak the SQLite adapter to allow in-memory databases. That would be easier.

Both already work, but only in test environment. It wouldn't be difficult to change. I can give you pointers if you can send a pull request adding this capability.

[bsr203]

sure. may be sqlite inMemory mode is better as we don't need other drivers and dependencies. I think it will be useful for testing in isolation. thanks

[radex]

Well, I assume you're already using the React native native module for SQLite, so there's no extra dependencies.

Loki should work too in-memory. We use that in common tests (but that runs in Node)

[bsr203]

so is there an easy way to configure the adapter to pass through :memory config

[radex]

I already said:

Both already work, but only in test environment. It wouldn't be difficult to change. I can give you pointers if you can send a pull request adding this capability.

[bsr203]

:-) I was asking about the pointers you said. quickly searched through the codebase and didn't find the driver setting. Sorry, didn't look through all the code yet.

[radex]

@bsr203 You'll have to start from this branch, not master, as there were changes in this area:

https://github.com/Nozbe/WatermelonDB/pull/70/files#diff-010253597e9bd62ff04e3105667f6b66R45

right now, the database name is passed directly to sqlite only in test mode, otherwise documents filesystem path is prepended.

This can be changed so that if dbName is :memory: or contains mode=memory, it's passed directly without prepending FS path.

I think this should work on Android without any changes. But if no, this is the line:

https://github.com/Nozbe/WatermelonDB/pull/70/files#diff-2050916f6706022d034a09ab20dd9ed4R14

You'll find instructions for Xcode / Android setup and running native tests in CONTRIBUTING.md file

[bsr203]

@radex thanks for the details. I probably can't get to it right away, and let you know. thanks.

[radex]

Closing this. @bsr203 feel free to ask Qs if you want to get to implementing this in the future