async function exposeFunctionIfAbsent(page, name, fn) {
    const exist = await page.evaluate((name) => {
        return !!window[name];
    }, name);
    if (exist) {
        return;
    }
    await page.exposeFunction(name, fn);
}
Expose a function to the page if it does not exist

NOTE:
Rewrite it to 'upsertFunction' after updating Puppeteer to 20.6 or higher
using page.removeExposedFunction
https://pptr.dev/api/puppeteer.page.removeExposedFunction

@param {import(puppeteer).Page} page
@param {string} name
@param {Function} fn