Improve navigation

[aslushnikov]

Navigation is hard.
Make sure the following navigation scenarios work properly:

• page.navigate('not-a-url') should return false
• page.navigate('https://expired.badssl.com/') should return false
• page.navigate('http://example.com/non-existing-page') should return false
• page.navigate('http://example.com') with no internet should return false
• page.navigate('data:text/html,hello') should return true
• Page's navigation via inner javascript's window.location.href = 'http://example.com' should be reported to puppeteer, probably via the Navigated event.

All of this should be also applicable to frame navigation in #4

[aslushnikov]

Today, 'page.navigate' waits for the load event to fire. We might need an option to wait for DOMContentLoaded instead, though I don't know a scenario where this is useful.

[JoelEinbinder]

example.com returns status 200 for all paths, so that non-existing-page case won't work. Is the idea to return false for non-200 status codes? I feel like the true/false should be whether or not the current page was rendered with data from that url. So 403/404/200 would be true, but timeout/brokenssl would be false.

[paulirish]

Rather than false, to me it seems better to reject with an Error with a more descriptive message.

[aslushnikov]

So the issue with returning true/false is that it's hard to decide what is a success and what is a failure. For example, navigating to a 404 page might be a valid scenario, since a lot of websites have their own custom-made 404's.

How about:

• we consider navigation failed if there's a navigation timeout or an interstitial
• anything else returns a status code for the main resource

This should address both @JoelEinbinder and @paulirish concerns. What do you guys think?

[paulirish]

it could return the fetch response object for the main resource