Updated 2018-05-23:
The port is now poudriere-compatible.
An unofficial Electron org has been set up here, help is always welcome! https://github.com/freebsd-electron
Current working repo: https://github.com/yzgyyang/freebsd-ports-electron
Also started to submit patches and feature requests to upstream:
https://github.com/electron/native-mate/pull/21
https://github.com/electron/electron/issues/12413
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Updated 2018-02-25:
Switched to use Electron 1.8 beta. Ongoing discussions can be found at Add FreeBSD support to electron #3797 electron/electron - GitHub
qbit@github, who maintains OpenBSD's port of Node.js, tried building an Electron port last year without success. https://deftly.net/posts/2017-06-01-measuring-the-weight-of-an-electron.html
Still fixing the code and conducting tests. Electron/Atom build process is extremely convoluted and complex, so there is no estimated time for this.