Is it possible to override a method of the base widget using a widget-subclass?

[BurningTreeC]

I would like to override the refreshChildren method of the base widget (widget.js) using a widget-subclass

Is that possible somehow? I'm trying my best but with no luck...

[BurningTreeC]

I found out that I can do this in a startup module. But would that be the preferred option?

Thank you,
Simon

[pmario]

It would be interesting, what you try to achieve?

From my point of view modifying the "base" widget class in a plugin is a no go, since every other widget will inherit from the base widget. Chances are very high, that there will be unwanted side effects.

Usually we create a user-widget, which inherits from widget and then overwrite the refresh mechanism in only 1 user-widget.

[BurningTreeC]

What I'm trying to achieve is, that ALL widgets do an additional check in the refreshChildren method

[pmario]

How exactly should that look like. Would it make sense for the core to have this "check" built in already. So you would not need to "patch" it?

[Jermolene]

Hi @BurningTreeC it would indeed be interesting to know what you're trying to achieve. Overriding a base class does seem like it should be a last resort.

[BurningTreeC]

Hi @pmario @Jermolene

What I'm trying to achieve is the following:

• don't refresh widgets that have a domNode that has a certain style
• in my case the style is content-visibility: auto

Why?

In my TiddlyFlex layout tiddlers that are outside of the visible areas get the style content-visibility: auto and contain-intrinsic-size set to the width and height of the elements. Like that, if browsers don't render the element because of content-visibility: auto, it still takes up its original height and width and with a resizeObserver I can detect if they resize even if they are outside of the view and can then re-calculate their dimensions or if they're visible.

Now, refreshing a tiddler with content-visibility: auto doesn't make sense. It makes sense doing it when its content-visibility-state changes to visible and I'm doing that. There are also big performance improvements possible if tiddlers with content-visibility: auto don't get refreshed.

How I'm doing it (and I don't say that it's the correct way) is overriding the base widget refreshChildren method with the following code:

var Widget = require("$:/core/modules/widgets/widget.js").widget;

Widget.prototype.refreshChildren = function(changedTiddlers,force) {
	var children = this.children,
		refreshed = false;
	for(var i=0; i<children.length; i++) {
		var child = children[i];
		if(!force && child.domNodes && child.domNodes[0] && child.domNodes[0].style && ((child.domNodes[0].style["content-visibility"] === "auto") || (child.domNodes[0].style["content-visibility"] === "hidden"))) {
			return false;
		} else {
			refreshed = child.refresh(changedTiddlers) || refreshed;
		}
	}
	return refreshed;
};

I really don't know if this is something for the core @pmario ... even if it makes sense not refreshing tiddlers with those styles ...

Thank you for your attention!
Simon

[pmario]

I really don't know if this is something for the core @pmario ... even if it makes sense not refreshing tiddlers with those styles ...

You already use the dynaview-plugin. So it may have a place there?

[BurningTreeC]

I use the dynaview-plugin ONLY to get the viewport dimensions in state tiddlers. For nothing else. I made a custom dynanode widget which does things like checking if an element is visible within a given node.

[BurningTreeC]

P.S. yes, the question is, what to do if a tiddler outside of the view transcludes a tiddler that is within the view and if that tiddler's content changes and that would cause the tiddler out of view to resize, what to do in that case... I'm testing that 😸

[BurningTreeC]

I found my answer: it's not needed. 😄