in scrooge-generator-typescript/src/main/scala/com/gu/scrooge/backend/typescript/TypescriptGenerator.scala [118:123]
def namespacedFolder(destFolder: File, namespace: String, dryRun: Boolean): File = {
val cleanedNamespace = packageNameFromNamespace(namespace)
val file = new File(destFolder, cleanedNamespace)
if (!dryRun) file.mkdirs()
file
}