validate email format

lib/params/base_validator.rb

@@ -2,6 +2,8 @@
 
 module Params
   class BaseValidator
+    EMAIL_REGEXP = /\A[a-z0-9][\.']?(?:(?:[a-z0-9_-]+[\.\+'])*[a-z0-9_-]+)*@(?:[a-z0-9]+[\.-])*[a-z0-9]+\.[a-z]{2,}\z/i
+
     InvalidParameterError = Class.new(StandardError)
 
     def self.call(...)
@@ -65,6 +67,14 @@ module Params
       raise_error(message || "#{key} must follow the #{regexp.source} format")
     end
 
+    def email_format(params, key, message: nil)
+      return if params.blank?
+      return if params[key].blank?
+      return if params[key].to_s.strip.split(/\s*[;,]\s*/).all? { |email| email.match?(EMAIL_REGEXP) }
+
+      raise_error(message || "#{key} must follow the email format")
+    end
+
     def unique_value(params, key, message: nil)
       return unless params.is_a?(Array)
       return if params.none?