Grav-Admin-Plugin/themes/grav/app/utils/tabs-memory.js

import $ from 'jquery';
import Cookies from 'cookies-js';
import { Instance as Editors } from '../forms/fields/editor';

let Data = JSON.parse(Cookies.get('grav-tabs-state') || '{}');

$('body').on('touchstart click', '[name^="tab-"]', (event) => {
    event && event.stopPropagation();
    let target = $(event.currentTarget);

    Data[target.attr('name')] = target.val();
    Cookies.set('grav-tabs-state', JSON.stringify(Data), { expires: Infinity });

    Editors.editors.each((index, editor) => {
        let codemirror = $(editor).data('codemirror');
        if (!codemirror) { return; }
        if (codemirror.display.lastWrapWidth === 0) {
            codemirror.refresh();
        }
    });
});