How to add to a serialized array
You can pass a class to serialize:
class User < ActiveRecord::Base serialize :recent_messages, ArrayendThe above ensures that recent_messages is an Array:
User.new#=> #<User id: nil, recent_messages: [], created_at: nil, updated_at: nil>Note that you might have to convert existing fields if the types don't match.
It's because the first time you try to push an item to your recent_messages, there's no array to push the item into (the field is nil by default). So you must create the array before you can push to it
@user = current_userif @user.recent_messages.nil? @user.recent_messages = [params[:message]]else @user.recent_messages << params[:message]end@user.save
You can also try following code:- By default @user.recent_messages would be nil
@user.recent_messages ||= []@user.recent_messages << params[:message]@user.save