<% @posts.each do |post| %>

    ....
    ....
    ....

    <%= react_component(
      "CommentBox",
      post_id: post.id,
      user_name: current_user.to_s,
      comments: ActiveModel::ArraySerializer.new(
        post.comments.includes(:user),
        each_serializer: CommentSerializer
      ).to_json
    ) %>
<% end %>