conditional-deployment.json

{
  "condition": "[equals(parameters('newOrExisting'),'new')]",
  "type": "Microsoft.Storage/storageAccounts",
  "apiVersion": "2017-06-01",
  "name": "[variables('storageAccountName')]",
  "location": "[parameters('location')]",
  "sku": {
    "name": "[variables('storageAccountType')]"
  },
  "kind": "Storage",
  "properties": {}
}