Zodのunion型で最初にマッチしたスキーマによりプロパティが切り落とされる挙動について

const UserSchema = z.object({
  canRead: z.boolean(),
  canWrite: z.boolean(),
  approvalNotificationEmail: z.string()
});

const ManagerSchema = z.object({
  canApprove: z.boolean(),
  canDelete: z.boolean(),
  approvalRequestNotificationEmail: z.string(),
});

const AdminSchema = z.object({
  canRead: z.boolean(),
  canWrite: z.boolean(),
  canApprove: z.boolean(),
  canDelete: z.boolean(),
  approvalNotificationEmail: z.string(),
  approvalRequestNotificationEmail: z.string(),
});

// ユニオン型
const AllRolesSchema = z.union([UserSchema, ManagerSchema, AdminSchema]);

const setting = {
  canRead: true,
  canWrite: false,
  canApprove: false,
  canDelete: false,
  approvalNotificationEmail: "user@example.com",
  approvalRequestNotificationEmail: "manager@example.com",
}

// 検証
const result = AllRolesSchema.safeParse(setting);

{
  canRead: true,
  canWrite: false,
  canApprove: false,
  canDelete: false,
  approvalNotificationEmail: 'user@example.com',
  approvalRequestNotificationEmail: 'manager@example.com'
}

{
  canRead: true,
  canWrite: false,
  approvalNotificationEmail: 'user@example.com'
}

const UserSchema = z.object({
  role: z.literal('user'),
  canRead: z.boolean(),
  canWrite: z.boolean(),
  approvalNotificationEmail: z.string()
});

const ManagerSchema = z.object({
  role: z.literal('manager'),
  canApprove: z.boolean(),
  canDelete: z.boolean(),
  approvalRequestNotificationEmail: z.string(),
});

const AdminSchema = z.object({
  role: z.literal('admin'),
  canRead: z.boolean(),
  canWrite: z.boolean(),
  canApprove: z.boolean(),
  canDelete: z.boolean(),
  approvalNotificationEmail: z.string(),
  approvalRequestNotificationEmail: z.string(),
});

// discriminatedUnionを使ったunion型の作成
const AllRolesSchemaWithDiscriminator = z.discriminatedUnion('role', [
  UserSchema,
  ManagerSchema,
  AdminSchema,
]);

const setting = {
  role: "admin",
  canRead: true,
  canWrite: false,
  canApprove: false,
  canDelete: false,
  approvalNotificationEmail: "user@example.com",
  approvalRequestNotificationEmail: "manager@example.com",
}

const result = AllRolesSchemaWithDiscriminator.safeParse(setting);

{
  role: 'admin',
  canRead: true,
  canWrite: false,
  canApprove: false,
  canDelete: false,
  approvalNotificationEmail: 'user@example.com',
  approvalRequestNotificationEmail: 'manager@example.com'
}

type AllRoles = z.infer<typeof AllRolesSchemaWithDiscriminator>;

const handle = (data: AllRoles) => {
  if (data.role === "user") {
    console.log(data.canRead);
    console.log(data.canDelete); // エラー
  }
}

// ユニオン型
// より具体的なAdminSchemaを一番前にもってくる
const AllRolesSchema = z.union([AdminSchema, UserSchema, ManagerSchema]);

// strictObject
const UserSchema = z.strictObject({
  canRead: z.boolean(),
  canWrite: z.boolean(),
  approvalNotificationEmail: z.string()
});

// strict
const UserSchema = z.object({
  canRead: z.boolean(),
  canWrite: z.boolean(),
  approvalNotificationEmail: z.string()
}).strict();

// パフォーマンステスト
const iterations = 100000;
const start = performance.now();

for (let i = 0; i < iterations; i++) {
  AllRolesSchema.safeParse(setting);
}

const end = performance.now();
console.log(`${iterations} iterations: ${(end - start).toFixed(2)}ms`);