Is using zod for type narrowing fine solution?

let a = await dbDrizzle.query.document.findFirst({
    with: {
        lines: true
    },
}).then(r => {
    if (!r) throw new Error('Document not found')
    if (r.typ === 'order') {
        const lineSchema = orderLineSchema
        return orderSchema.extend({lines: z.array(lineSchema)}).parse(r)
    } else if (r.typ === 'receipt') {
        const lineSchema = receiptLineSchema
        return receiptSchema.extend({lines: z.array(lineSchema)}).parse(r)
    }
})