#### Workbook File Properties

The various file formats use different internal names for file properties.  The
workbook `Props` object normalizes the names:

| JS Name     | Excel Description              |
|:------------|:-------------------------------|
| Title       | Summary tab "Title"            |
| Subject     | Summary tab "Subject"          |
| Author      | Summary tab "Author"           |
| Manager     | Summary tab "Manager"          |
| Company     | Summary tab "Company"          |
| Category    | Summary tab "Category"         |
| Keywords    | Summary tab "Keywords"         |
| Comments    | Summary tab "Comments"         |
| LastAuthor  | Statistics tab "Last saved by" |
| CreatedDate | Statistics tab "Created"       |

For example, to set the workbook title property:

```js
if(!wb.Props) wb.Props = {};
wb.Props.Title = "Insert Title Here";
```

Custom properties are added in the workbook `Custprops` object:

```js
if(!wb.Custprops) wb.Custprops = {};
wb.Custprops["Custom Property"] = "Custom Value";
```