MessageCatcherWidget

22nd December 2021 at 3:30pm

Introduction

The message catcher widget traps messages dispatched within its child content, and allows invoking a series of ActionWidgets in response to those messages.

Content and Attributes

The content of the <$messagecatcher> widget is displayed normally.

Attribute	Description
{any attributes starting with $}	Each attribute name (excluding the $) specifies the name of a message, and the value specifies the action string to be invoked
type	Name of the message be trapped, for example "tm-scroll" or "tm-navigate". The `type` and `actions` attributes can be useful when the type of event needs to be specified via a variable or text reference
actions	Action string to be invoked when a matching message is trapped. Must be used in conjunction with the `type` attribute

Variables

The message catcher widget sets the following variables within each action string:

Variables	Description
`event-*`	All string-based properties of the `event` object, with the names prefixed with `event-`
`list-event`	A list of the names of each the string-based properties of the `event` object (the names are not prefixed with `event-`)
`event-paramObject-*`	All string-based properties of the `event.paramObject` object, with the names prefixed with `event-paramObject-`
`list-event-paramObject`	A list of the names of each the string-based properties of the `event.paramObject` object (the names are not prefixed with `event-paramObject-`)
`modifier`	For messages that originated with browser events, the modifier keys that were pressed when the event was fired. The possible modifiers are normal (no modifiers), ctrl, ctrl-alt, ctrl-shift, alt, alt-shift, shift and ctrl-alt-shift

Example


\define actions()
<$action-log/>
\end

<$messagecatcher $tm-navigate=<<actions>>>

Click on [[this link]] to fire an action. See the browser JavaScript console for the output

</$messagecatcher>

That renders as:

Click on this link to fire an action. See the browser JavaScript console for the output