If you play around with Azure Functions, you might notice that the cold start times for Azure Functions that have C# as the language are just a few seconds. However, if you are working with Azure Functions that have JavaScript (such as Node.js) as the language, then the cold start time would be greater as the runtime would need to download all the npm packages that are dependencies for your application. In those scenarios, a feature named Run-From-Package comes in very handy. We will learn how to implement this in the upcoming chapter.