Preventing Widget deletion

v6
1

Hello,

I have a widget which adds a Google Maps embedding. The problem is that when I scroll below and the map goes out of the viewport, the DOM node gets deleted, and recreated when back in view so the zoom level I set is gone.

Is there any way to prevent widgets of a certain widget type from getting deleted?

2

No. Content outside of the viewport is removed from the DOM. You may, if the maps widget can handle being detached and reattached, be able to set up something like a caching layer where you reuse the same rendered DOM on a re-render, but the editor itself won’t keep out-of-view content in the DOM.

3

Do you mean something like doing a removeChild when the Widget’s destroy method is called and returning the node returned by removeChild when toDOM is called?

I tried the following and it doesn’t seem to work:

let elements = [];
for (let i = 0; i < 1000; i++) {
    // elements.push(htmlToElement('<input type="checkbox"/>'))
    elements.push(htmlToElement(mapHTML))
}

class MapWidget extends WidgetType {

    destroy(dom: HTMLElement) {
        let child = dom.removeChild(dom.firstChild);
        console.log("caching ", child);
        elements[this.index] = child;
    }

    toDOM(view: EditorView) {
        const container = document.createElement('div')
        container.appendChild(elements[this.index]);
        return container;
    }

I’d appreciate any ideas.

4

Ah, is this because the widget’s destroy method is getting called after ContentView’s destroy is called here: https://github.com/codemirror/view/blob/e1c63cf342ed22aa31d6d0647093f20605f3fc9c/src/blockview.ts#L244 ?