Custom Sitecore JSS Layout Processor

ErrorsLayoutServiceContextProcessor.cs

    /// <summary>
    /// Extends the LayoutService context with localized errors.
    /// </summary>
    public class ErrorsLayoutServiceContextProcessor : JssGetLayoutServiceContextProcessor
    {
        public ErrorsLayoutServiceContextProcessor(IConfigurationResolver configurationResolver) : base(configurationResolver)
        {
        }

        protected override void DoProcess(GetLayoutServiceContextArgs args, AppConfiguration application)
        {

            if(args.RenderedItem == null || application == null)
            {
                return;
            }

            var errorItems = Sitecore.Context.Database?.GetItem(application.Attributes["generalErrorsRoot"])?.Children;

            if (errorItems == null)
            {
                return;
            }

            var errors = new Dictionary<string, ErrorDTO>();

            foreach (Item item in errorItems)
            {
                var code = item.Fields[Templates.Error.Fields.Code]?.Value;
                if (string.IsNullOrEmpty(code))
                {
                    continue;
                }

                errors.Add(code, new ErrorDTO()
                {
                    Description = item.Fields[Templates.Error.Fields.Description]?.Value,
                    Message = item.Fields[Templates.Error.Fields.Message]?.Value,
                    Type = item.Fields[Templates.Error.Fields.Type]?.Value
                });
            }

            args.ContextData.Add("errors", errors);
        }

        private class ErrorDTO
        {
            public string Description { get; set; }
            public string Message { get; set; }
            public string Type { get; set; }
        }
    }