What are the best options for programatically creating an Azure Storage Account with Javascript? I've found Javascript libraries that allow you to manage Blob storage etc. once a Storage Account is created, however they do not seem to enable creating a Storage Account itself.
You could not create a storage account with javascript. The offical document has explained in the Getting started. And @azure/storage-blob is used to consume Microsoft Azure Storage Blob service.
Prerequisites: You must have an Azure subscription and a Storage Account to use this package. If you are using this package in a Node.js application, then Node.js version 8.0.0 or higher is required.
As r2018 said in the comment, you can either use Portal, PowerShell or Azure CLI to create it, see here.