Setting window.opener to null only works in browsers

[alexdima]

Extracted from #601 (comment)
From @hawkerm

Regarding #601

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I'm running Monaco in a x-ms-webview, so 10.1.0 broke that as I wouldn't get the uri in the new window request anymore (only about:blank).

Saw there were some updates for this code path in the vscode tree to detect if it was a 'native' platform. Not sure if that'll detect the x-ms-webview case as well, but want to make sure this scenario can be covered too.

[alexdima]

I'm not sure how to detect running in an x-ms-webview...

[hawkerm]

@alexandrudima would it make sense to provide a setting that can turn this behavior off and make the original call to window.open?

Here's the line in vs code, but they have a flag platform.isNative, but I'm not sure how/where that's set.

[alexdima]

@hawkerm Is there any way at runtime for us to detect this special case? For example, this is how we detect the isNative case:

https://github.com/Microsoft/vscode/blob/52007064712fb8e74e8b7dd00903beaabcd79648/src/vs/base/common/platform.ts#L45

if (typeof process === 'object' && typeof process.nextTick === 'function' && typeof process.platform === 'string')

Perhaps there is a way for us to detect running under an x-ms-webview ?

[hawkerm]

@alexandrudima how about just looking at the user agent string? It has WebView in the platform:

Mozilla/5.0 (Windows NT 10.0; WOW64; WebView/3.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16299

Compared to the browser in Edge:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16299

The Windows WebView has an event for opening new windows which requires the developer using the webview to decide what to do with the requested new window. It doesn't pass a reference or have any context from the requesting page, so its not susceptible to the opener issue.

[hawkerm]

Awesome, thanks for working towards a solution!