advantage of tap method in ruby

Question

I was just reading a blog article and noticed that the author used tap in a snippet something like:

user = User.new.tap do |u|
  u.username = \         


        

Answer 1

In rails we can use tap to whitelist parameters explicitly:

def client_params
    params.require(:client).permit(:name).tap do |whitelist|
        whitelist[:name] = params[:client][:name]
    end
end