Puppeteer Button Press

Perhaps another option could be:

await page.keyboard.press('Enter');

Leveraging its virtual keyboard API. More info info here

I've figured it out finally. I found inside that same form an anchor element whose type was submit. I then clicked on it and the form was submitted.

Here's the code I've used:

const form = await page.$('a#topbar-search');
await form.evaluate( form => form.click() );

You can also use the $eval method instead of evaluate:

await page.$eval( 'a#topbar-search', form => form.click() );