----------------------------
Development with MKWS consists primarily of defining new types of
-widgets. These can interact with the core functionality is several
-defined ways.
+widgets. This is done using exactly the same API as the the widgets
+that come as part of the set: they have no privileged access.
You create a new widget type by calling the `mkws.registerWidgetType`
function, passing in the widget name and a function. The name is used
to recognise HTML elements as being widgets of this type -- for
-example, if you register a `Foo` widget, elements like
-`<div class="mkwsFoo">` will be widgets of this type.
+example, if you register a `foo` widget, elements like
+`<div class="mkws-foo">` will become widgets of this type.
-The function promotes a bare widget object (passed as `this`) into a
+The function promotes a bare widget object (which is created by the
+core widget code and passed in as `this`) into a
widget of the appropriate type. MKWS doesn't use classes or explicit
prototypes: it just makes objects that have the necessary
behaviours. There are _no_ behaviours that Widgets are obliged to
provide: you can make a doesn't-do-anything-at-all widget if you like:
- mkws.registerWidgetType('Sluggard', function() {});
+ mkws.registerWidgetType('sluggard', function() {});
More commonly, widgets will subscribe to one or more events, so that
they're notified when something interesting happens. For example, the
-`Log` widget asks to be notified when a `log` event happens, and
+`log` widget asks to be notified when a `log` event happens, and
appends the logged message to its node, as follows:
- mkws.registerWidgetType('Log', function() {
+ mkws.registerWidgetType('log', function() {
var that = this;
this.team.queue("log").subscribe(function(teamName, timestamp, message) {
* You can add functionality to a widget by subscribing it to an
event's queue using `this.team.queue("EVENT").subscribe`. The
argument is a function which is called whenever the event is
- published. The arguments to the function are different for different
- events.
+ published. The arguments to the event-callback function are
+ different for different events.
* As with so much JavaScript programming, the value of the special
- variable `this` is lost inside the `subscribez` callback function,
+ variable `this` is lost inside the `subscribe` callback function,
so it must be saved if it's to be used inside that callback
(typically as a local variable named `that`).
-----------------------------------
Many widgets are simple specialisations of existing widgets. For
-example, the `Record` widget is the same as the `Records` widget
-except that it defaults to displaying a single record. It's defined as
-follows:
+example, the `images` widget is the same as the `records` widget
+except that it defaults to using the `images` template for displaying
+its result list. It's defined as follows:
- mkws.registerWidgetType('Record', function() {
- mkws.promotionFunction('Records').call(this);
- if (!this.config.maxrecs) this.config.maxrecs = 1;
+ mkws.registerWidgetType('images', function() {
+ mkws.promotionFunction('records').call(this);
+ if (!this.config.template) this.config.template = 'images';
});
Remember that when a promotion function is called, it's passed a base
the promotion function that's been registered for that type.
Once this has been done, the specialisations can be introduced. In
-this case, it's a very simple matter of changing the `maxrecs`
-configuration setting to 1 unless it's already been given an explicit
-value. (That would occur if the HTML used an element like `<div
-class="mkwsRecord" maxrecs="2">`, though it's not obvious why anyone
-would do that.)
+this case, it's a very simple matter of changing the `template`
+configuration setting to `'images'` unless it's already been given an
+explicit value. (That would occur if the HTML used an element like
+`<div class="mkws-images" template="my-images">` to use a customised
+template.
Reference Guide
be used by the derived widget.
* `String this.type` --
- A string containing the type of the widget.
+ A string containing the type of the widget (`search`,
+ `switch`, etc.)
* `Team this.team` --
The team object to which this widget belongs. The team has
below.
* `DOMElement this.node` --
- The DOM element of the widget
+ The DOM element of the widget. Most often used for inserting
+ HTML into the widget element.
* `Hash this.config` --
A table of configuration values for the widget. This table
inherits from the default configuration. Instances of widgets
in HTML can set configuration items as HTML attributes: for
example, the HTML element
- `<div class="mkwsRecords" maxrecs="10">`.
+ `<div class="mkwsRecords" maxrecs="10">`
creates a widget for which `this.config.maxrecs` is set to 10.
* `String this.toString()` --
widgets such as `Records` and `Facet` that display some part
of a search result.
-* `VOID hideWhenNarrow()` --
- Registers that this widget should hide itself when the page
- becomes "narrow" -- that is, fewer pixels in width that the
- threshhold value specified by the top-level configuration item
- `responsive_design_width`. Should be used for "unimportant"
- widgets that can be omitted from the mobile version of a site.
-
-* `expandValue()` --
- TODO: either document this or remove it from the API.
-
* `subwidget(type, overrides, defaults)` --
Returns the HTML of a subwidget of the specified type, which
can then be inserted into the widget using the
except where overrides are passed in. If defaults are also
provided, then these are used when the parent widget provides
no values. Both the `overrides` and `defaults` arguments are
- hashes: the latter is optional.
-
- See for example the `Credo` widget defined in the example
- area's `mkws-widget-credo.js` file. This uses several
- invocations of `subwidget` to create a complex compound widget
- with numerous text, facet and image panes. TODO: rename this
- widget and everything related to it.
+ hashes: the latter is optional. This can be used to assemble
+ compound widgets containing several subwidgets.
In addition to these properties and methods of the bare widget object,
some kinds of specific widget add other properties of their own. For
Events
------
-TODO: list of events that can be usefully subscribed to.
+FIXME: list of events that can be usefully subscribed to.
- - -