CRDT Guidelines

Critical: Draft-Style Mutations Only

// CORRECT - mutate in place
setState((state) => {
    state.transactions[id] = transaction;
});

// WRONG - returning new objects breaks change tracking
setState((state) => ({
    ...state,
    transactions: { ...state.transactions, [id]: transaction }
}));

Rules

• Import types from schema.ts, don't redeclare
• Soft deletes: Set deletedAt = Temporal.Now.instant(), never remove from document
• undefined deletedAt means "not deleted" (falsy check: if (!entity.deletedAt))
• Use crypto.randomUUID() for IDs, Temporal.Now.instant() for timestamps

Rich Domain Types (via rich-schema.ts transforms)

Schema fields use richSchema.* helpers that apply bidirectional transforms between CRDT primitives and domain types. The richSchema factory methods must be generic over O extends SchemaOptions to preserve required: false optionality.

richSchema helper	CRDT primitive	Domain type
richSchema.PlainDate()	string	Temporal.PlainDate
richSchema.Instant()	number	Temporal.Instant
richSchema.MoneyMinorUnits()	number	MoneyMinorUnits
richSchema.Percentage()	number	Percentage
richSchema.CurrencyCode()	string	CurrencyCode
richSchema.StringEnum(values)	string	Union literal type

Schema Pattern

export const entitySchema = schema.LoroMap({
    id: schema.String({ required: true }),
    name: schema.String({ required: true }),
    // Optional fields use { required: false } — value type becomes T | undefined
    deletedAt: richSchema.Instant({ required: false })
});

React Hooks

• useActiveTransactions() - excludes soft-deleted
• useTransactions() - includes soft-deleted
• useVaultAction() - for mutations

Sync

• Updates encrypted before leaving client
• Loro handles versioning via version vectors
• Conflicts: last-write-wins per field