conditional_validation_lambda

🔀 Conditional Validation with Lambdas

Use lambdas for if and unless to conditionally apply validations based on dynamic model state. This is particularly useful when validations depend on other attributes or external services.

class Order < ApplicationRecord
  validates :shipping_address, presence: true, if: ->(order) { order.shipped? }
  validates :tracking_number, presence: true, unless: ->(order) { order.expedited? }
end

# Usage
order = Order.new(shipped: true)
order.valid? # triggers shipping_address presence check