What happens when we get to this part of the code?

This approach might happen to work, but note how this if loop does not follow the model of the rest of this ffunction. Everything else is setCashtabSettings(localSettings) followed by return currency.defaultSettings

You don't have a return call here, so this function will still get to line 1138 and overwrite all settings with the default settings.

You're also calling this async function without await (all localforage calls are async) -- though in this case, the error is that parseInvalidSettingsForMigration is using localforage...it should not be.

This is where you want to do your business. If the function gets here, it means the user has a settings object but they are not valid for some reason.

In this case, you want to parse and see why they are invalid. If they are invalid because a param is missing, then add the default of that param and return the now-modified settings object.

Then setCashtabSettings(yourModifiedLocalSettings) and return yourModifiedLocalSettings` to keep consistent with the rest of the function.

import not needed

this function is only called on invalid settings. So, call the input invalidCashtabSettings

this function should not be async

You don't need this line, just use currency.defaultSettings

Before this, create a new settings object, migratedCashtabSettings = invalidCashtabSettings

Here, you want to change migratedCashtabSettings

It's not necessary for this function to touch localforage

Instead, return the now-correct migratedCashtabSettings

As mentioned in previous comments, localforage should not be in this function.

Might as well call isValidCashtabSettings(modifiedLocalSettings) just in case.

Return the default settings if invalid.

Comment no longer valid. Please update to reflect what is being done here now.

We need an else block here to handle the case where parseInvaldSettings for whatever reason generated an invalid settings object. In this case, it can be the same as the previous block that handles an invalid settings object.

else {
// if not valid, also set cashtabSettings to default
        setCashtabSettings(currency.defaultSettings);
        return currency.defaultSettings;
}

Unit tests for this function

Replace comment

// Since this is returning default settings based on an error from reading storage, do not overwrite whatever is in storage