Type Definitions

JSDuck checks that your type definitions (specified like {Number}) follow a rigid specification.

JSDuck supports a basic syntax which is used throughout ExtJS documentation and the syntax supported by Google Closure Compiler.

The basic syntax

This list covers what you can do with the basic syntax:

• {Ext.Element} - a single Ext.Element.
• {String[]} - array of strings.
• {String[][]} - 2D array of strings.
• {Number/String/Boolean} - either number, string, or boolean.
• {Boolean...} - variable number of boolean arguments.

These of course can be combined. For example:

• {String[]/Number[]...} - variable number of string or number arrays.

Google Closure Compiler Type Expressions

For more expressive power Google Closure Compiler Type Expressions allow you to write complex type expressions like this:

• {function((number|string), RegExp=): boolean} - a function taking two arguments (first a number or string, second a RegExp which is optional) and returning a boolean.

Type names

JSDuck will also check that you don't reference any unknown types. For example if you specify {Foo} and you don't have class Foo included to you documentation, JSDuck will produce a warning. Warnings aren't thrown for JavaScript primitive types:

• boolean
• number
• string
• undefined
• void

for built-in JavaScript types:

• Object
• String
• Number
• Boolean
• RegExp
• Function
• Array
• Arguments
• Date
• Error

and for few DOM types:

• HTMLElement
• XMLElement
• NodeList
• TextNode
• CSSStyleSheet
• CSSStyleRule
• Event

To make JSDuck ignore some other type names use --external=Foo,Bar,...

To document a variable that can be of any type whatsoever, use the Mixed type. But try to keep its use to the minimum, always prefer the {Foo/Bar/Baz} syntax to list possible types.