Check if element is attached to DOM is too specific

[nlundquist]

The check made here:

xterm.js/src/Terminal.ts

Line 457 in 71a78cb

if (!document.body.contains(parent)) {

before throwing a warning is too narrow. It fails when xterm is opened inside a parent element inside a WebComponent shadow root. document.body.contains(parent) will return false, even thought the parent is fully attached and visible on the page.

Details

• Browser and browser version: Firefox 71, Chrome 79
• OS version: OS X
• xterm.js version: 4.3.0

Steps to reproduce

1. Create a simple WebComponent rendering a single div
2. Use Terminal.open to create a new terminal inside that div
3. The warning will be produced even though the elements are fully attached and rendered

[nlundquist]

Perhaps parent.isConnected is really all the check that is needed?

[Tyriar]

@nlundquist sounds like that's what I was after, would you like to do a PR for this?