op-packages/luci-mod-dashboard/htdocs/luci-static/resources/view/dashboard/lib/widgets.js

'use strict';
'require baseclass';
'require fs';
'require uci';

const SLOTS = [ 'cards', 'charts', 'tabs' ];

return baseclass.extend({
	slots: SLOTS,

	load() {
		return L.resolveDefault(fs.list('/www' + L.resource('view/dashboard/include')), []).then(entries => {
			return Promise.all(entries.filter(e => {
				return (e.type == 'file' && e.name.match(/\.js$/));
			}).map(e => {
				return 'view.dashboard.include.' + e.name.replace(/\.js$/, '');
			}).sort().map(n => {
				return L.require(n);
			}));
		}).then(includes => {
			return Promise.all(includes.map(include => new Promise(resolve => {
				resolve((typeof(include.available) == 'function') ? include.available() : true);
			}).catch(e => {
				console.error(e);
				return false;
			}))).then(flags => includes.filter((include, i) => flags[i]));
		});
	},

	list(includes, slot) {
		return includes.reduce((list, include) => list.concat(include.widgets || []), [])
			.filter(widget => widget.slot == slot)
			.sort((a, b) => (a.order || 0) - (b.order || 0));
	},

	defaults(includes, slot) {
		return this.list(includes, slot).filter(widget => !widget.hidden).map(widget => widget.id);
	},

	// The ids to show in each slot, in display order. A slot that is not
	// configured shows its defaults: UCI cannot store an empty list, so
	// emptying one brings them back. Ids this device does not know, from
	// a restored config or typed by hand, are ignored.
	layout(includes) {
		const layout = {};

		return L.resolveDefault(uci.load('dashboard')).then(() => {
			SLOTS.forEach(slot => {
				const known = this.list(includes, slot).map(widget => widget.id);
				const ids = L.toArray(uci.get('dashboard', 'layout', slot)).filter((id, i, list) => {
					return known.includes(id) && list.indexOf(id) == i;
				});

				layout[slot] = ids.length ? ids : this.defaults(includes, slot);
			});

			return layout;
		});
	}
});