Base Classes

Devux provides base classes that your components extend. These handle common functionality like validation, transactions, and performance monitoring automatically.

Use-Case Base Classes

TransactionalUseCase

For endpoints that need database transactions.

@fullInjectable()
export class CreateCustomerUseCase extends TransactionalUseCase<CreateCustomerInput> {

    // Required: define transaction isolation level
    protected override getIsolationLevel(): TransactionIsolationLevel {
        return 'read-committed';
    }

    // Required: define transaction access mode
    protected override getAccessMode(): TransactionAccessMode {
        return 'read-write';
    }

    // Required: access control check
    protected override async _assertCanAccess(): Promise<void> {
        // Check if user can access this endpoint
    }

    // Required: your business logic
    protected override async _execute(input: CreateCustomerInput): Promise<void> {
        // Implementation
    }
}

Overridable methods:

Method	Default	Purpose
getTransactionMaxAttempts()	5	Max retry attempts on deadlock
getTransactionBaseDelayMillis()	50	Base delay between retries
getDurationThresholdMillis()	200	Slow use-case threshold for logging

Available methods:

• commit() - Manually commit the transaction
• rollback() - Manually rollback the transaction

NonTransactionalUseCase

For read-only endpoints or those that don't need transactions.

@fullInjectable()
export class GetCustomerUseCase extends NonTransactionalUseCase<GetCustomerInput> {

    protected override async _assertCanAccess(): Promise<void> {
        // Access control
    }

    protected override async _execute(input: GetCustomerInput): Promise<void> {
        // Implementation - no transaction wrapper
    }
}

Repo Base Classes

TransactionalRepo

For repos that run within a transaction context.

@fullInjectable()
export class CreateCustomerRepo extends TransactionalRepo<CreateCustomerRepoInput, CreateCustomerRepoOutput> {

    // Required: your database operation
    protected override async _execute(input: CreateCustomerRepoInput): Promise<CreateCustomerRepoOutput> {
        const customer = await this.trx
            .insertInto('customers')
            .values(input)
            .returningAll()
            .executeTakeFirstOrThrow();

        return { success: true, data: customer };
    }

    // Auto-generated by CLI
    protected override getRepoInputZodSchema() {
        return createCustomerRepoInputZodSchema;
    }

    // Auto-generated by CLI
    protected override getRepoOutputZodSchema() {
        return createCustomerRepoOutputZodSchema;
    }

    // Optional: map constraint violations to error codes
    protected override getUniqueKeyViolationErrorMap() {
        return {
            'customers_email_unique': CustomersErrorCodes['CustomerEmailAlreadyExists'],
        };
    }
}

Key property:

• this.trx - The transaction connection, shared across all repos in the use-case

Overridable methods:

Method	Default	Purpose
getDurationThresholdMillis()	50	Slow repo threshold for logging
getUniqueKeyViolationErrorMap()	{}	Map unique constraint names to error codes
getForeignKeyViolationErrorMap()	{}	Map foreign key constraint names to error codes

NonTransactionalRepo

For repos that don't need transaction context.

@fullInjectable()
export class GetCustomerRepo extends NonTransactionalRepo<GetCustomerRepoInput, GetCustomerRepoOutput> {

    protected override async _execute(input: GetCustomerRepoInput): Promise<GetCustomerRepoOutput> {
        const customer = await this.db
            .selectFrom('customers')
            .where('id', '=', input.customerId)
            .selectAll()
            .executeTakeFirst();

        if (!customer) {
            return { success: false, errorCode: CustomersErrorCodes['CustomerNotFound'] };
        }

        return { success: true, data: customer };
    }
}

Key property:

• this.db - The database connection pool

Domain Service Base Class

DomainServiceBase

For shared business logic across endpoints.

@fullInjectable()
export class CalculatePricingService extends DomainServiceBase<CalculatePricingInput, CalculatePricingOutput> {

    protected override async _execute(input: CalculatePricingInput): Promise<CalculatePricingOutput> {
        // Business logic
        return { success: true, data: { price: 100 } };
    }

    // Auto-generated by CLI
    protected override getServiceInputZodSchema() {
        return calculatePricingInputZodSchema;
    }

    // Auto-generated by CLI
    protected override getServiceOutputZodSchema() {
        return calculatePricingOutputZodSchema;
    }
}

Overridable methods:

Method	Default	Purpose
getDurationThresholdMillis()	100	Slow service threshold for logging

Performance Monitoring

All base classes automatically measure execution time. If an operation exceeds its threshold, the corresponding Core Hook is called:

• onSlowUseCase - Use-case exceeded threshold
• onSlowRepo - Repo exceeded threshold
• onSlowDomainService - Domain service exceeded threshold

Override getDurationThresholdMillis() for operations that legitimately take longer:

protected override getDurationThresholdMillis(): number {
    return 500; // This operation is expected to be slower
}

Automatic Validation

Repos and domain services automatically validate inputs and outputs against their Zod schemas during development. See Automatic Validation for details.