Obsidian QuickAdd script that opens & auto-updates today's daily note in the right sidebar.

pin-daily-note-in-sidebar.js

const SETTING_NAME = 'Reflesh interval (sec)';
const DEFAULT_SETTING = 10;

module.exports = {
    entry: async (params, settings) => {
        const { app, obsidian } = params;

        // Create WorkspaceLeaf (a tab in the right sidebar) which today's daily note will be opened in
        const leaf = app.workspace.getRightLeaf(false);
        // Open today's daily note in the leaf
        await updateLeafFile(leaf, app, obsidian);
        // Show the leaf (tab in sidebar)
        app.workspace.revealLeaf(leaf);

        // get reflesh interval from the user's settings
        const refleshInterval = +(settings[SETTING_NAME] || DEFAULT_SETTING);
        // register auto-update of the daily note opened in the sidebar
        // It will be disabled when closing the leaf (tab).
        const component = new obsidian.Component();
        component.load();
        component.registerInterval(
            window.setInterval(() => {
                if (leaf.parent) {
                    updateLeafFile(leaf, app, obsidian);
                } else {
                    leaf.detach();
                    component.unload();
                }
            }, refleshInterval * 1000)
        );
    },
    settings: {
        name: "Pin Daily Note in Sidebar",
        author: "Ryota Ushio",
        options: {
            [SETTING_NAME]: {
                type: 'text',
                defaultValue: DEFAULT_SETTING,
            }
        }
    }
}

/**
 * Get the settings of the core Daily Notes plugin.
 */
function getDailyNoteOptions(app) {
    const options = Object.assign(
        {},
        app.internalPlugins.plugins['daily-notes'].instance.options
    );
    options.format = options.format || 'YYYY-MM-DD';
    return options;
}

/**
 * Get today's daily note as TFile.
 */
async function getTodaysDailyNote(app, obsidian) {
    const { moment, normalizePath } = obsidian;
    const { folder, format } = getDailyNoteOptions(app);
    const path = normalizePath(`${folder}/${moment().format(format)}.md`);
    let file = app.vault.getAbstractFileByPath(path);
    if (!file) {
        // create it if it does not exist
        file = await app.vault.create(path, '');
    }
    return file;
}

/**
 * Update the daily note opened in the leaf.
 */
async function updateLeafFile(leaf, app, obsidian) {
    // get today's daily note as TFile
    const file = await getTodaysDailyNote(app, obsidian)
    if (leaf.view.file != file) {
        await leaf.openFile(file, { active: false });
    }
}