Create a CosmosDb User Defined Function using .NET SDK

CreateCosmosDbUdf.cs

using Microsoft.Azure.Cosmos;
using Microsoft.Azure.Cosmos.Scripts;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Threading.Tasks;

namespace GoesHere
{
    public class ClassName
    {
    
        pubic void DoStuff()
        {
            // assume have CosmosClient
            
            var databaseResponse = await cosmosClient.CreateDatabaseIfNotExistsAsycn(...);
            
            var cosmosScripts = database.Database.GetContainer(container.Name).Scripts;
        }

        private static async Task CreateUdf(Scripts cosmosScripts, string fn)
        {
            var response = await cosmosScripts.CreateUserDefinedFunctionAsync(new UserDefinedFunctionProperties
            {
                Id = fn,
                Body = Udf.Functions[fn]
            });
        }

        private static async Task<bool> UdfAlreadyExists(Scripts cosmosScripts, string fn)
        {
            bool udfExists;
            try
            {
                UserDefinedFunctionResponse udfResponse = await cosmosScripts.ReadUserDefinedFunctionAsync(fn);
                udfExists = true;
            }
            catch (CosmosException ex)
            {
                if (ex.StatusCode == HttpStatusCode.NotFound)
                {
                    udfExists = false;
                }
                else
                {
                    throw;
                }
            }

            return udfExists;
        }
    }
}