Javascript return values discrepancies

While I am integrating WebView2 into wxWidgets somebody came across the following discrepancies in javascript return values between Edge and Edge via WebView2 APIs ExecuteScript(). I'm pretty sure these are a problem in the WebView2 API:

A small javascript function f(){var person = new Object();}f(); returns this:

Return undefined
Edge backend: "null"
IE backend: "undefined"
Edge browser: "undefined"

This script returns function f(){var d = new Date('10/08/2017 21:30:40'); var tzoffset = d.getTimezoneOffset() * 60000; return new Date(d.getTime() - tzoffset);}f();:

Return date
Edge backend: "{}"
Edge browser: "Sun Oct 08 2017 23:30:40 GMT+0200 (Central European Summer Time)"
IE 11 browser: "Sun Oct 08 2017 23:30:40 GMT+0200 (Central Europe Daylight Time)"
Firefox: "Sun Oct 08 2017 23:30:40 GMT+0200 (Central European Summer Time)"

https://github.com/wxWidgets/wxWidgets/pull/1700#issuecomment-575794999

AB#28632017

Start with the WebView2 ExecuteScript() API behavior described in the issue and review the linked wxWidgets pull-request discussion. Reproduce the undefined and Date return-value cases using the listed scripts, then document the confirmed behavior or resolution for each discrepancy.