(lix sdk) use null | T instead of undefined | T

[samuelstroschein]

Context

kysely-org/kysely#27 (comment)

Proposal

Define database schema types as null | T instead of undefined | T to avoid bugs.

[samuelstroschein]

Using T | null leads to breaking changes for newly added (optional) columns.

Here is a reproduction https://www.typescriptlang.org/play/?#code/C4TwDgpgBAcgrgGwQQwEYIgFTRqBeKAbwCgBIAE2WGQC4oBBAJ0eRACE4AzTiRgbjIBbCNUrU6AJQgBjAPaNyAHgDOwRgEsAdgHMANFGSaQAPigAfKJsQIBAXwHFQkKAFVN5CJy04sP-ETIxWgZmVg5uXgFSYVEqZAB+SRl5JVUNHX1DEzsHOU1VKGp0CHgkHzpSlGLsYv8SCji6TQgAdxCWdi4eRgAKAAYASl1ie2JiPIKijDcPL01y13dPb2q-Anqgptb2sK7efqGR3Nl82QwAOgRZbR6pkusffTuZ5fnigaA.

Adding a column to a table and marking it with null, leads to breaking changes everywhere the type SomeTable or Selectable<SomeTable> is used.

type SomeTable = {
	data: ArrayBuffer;
+	metadata: Record<string, any> | null;
}; 

Additional context

• Casting `null` to undefined everywhere in kysely will lead to bugs down the road like an insert not being able to distinguish between null and undefined or JSON parsing failing
• TypeScript considers null as harmful https://github.com/Microsoft/TypeScript/wiki/Coding-guidelines#null-and-undefined
• The Supabase JS client has a similar discussion [Feature Request] - Option for nulls as undefined supabase/supabase-js#244