Dynamic case statement building for MySQL updates

[MattyD-Pave]

I'm having a lot of type issues around building a case statement from dynamic data... trying to build out the following query (MySQL)

UPDATE user
SET json_data = CASE
    WHEN email = '[email protected]'
    THEN JSON_ARRAY_APPEND(json_data, '$', JSON_OBJECT('some', 'data'))
    WHEN email = '[email protected]'
    THEN JSON_ARRAY_APPEND(json_data, '$', JSON_OBJECT('some', 'other data'))
    END
WHERE email IN ('[email protected]', '[email protected]');

The function generating this receives the update values in the form of a dictionary, like the following...

update_data = {
    a@example.com: { some: 'data' },
    b@example.com: { some: 'other data' }
}

This data can be variable, so i have to build a case statement dynamically, which results in type errors as mentioned in this comment. However, i have no workaround other than exiting the type system to build a case statement. even without reduce, here's an example...

    let caseStatement = kysely.case()
    for (const [email, data] of Object.entries(dataByEmail)) {
      caseStatement = caseStatement.when('email', '=', email).then(<JSON_ARRAY_APPEND Call>);
    }
    caseStatement = caseStatement.end();

TS2322: Type CaseWhenBuilder<DB, keyof DB, unknown, any> is not assignable to type CaseBuilder<DB, keyof DB, unknown, never>
Property #private in type CaseWhenBuilder refers to a different member that cannot be accessed from within type CaseBuilder

Any tips here?