Hello!
I am not sure if I missed it somewhere, but I did not see any instructions explaining the requirements for OpenSSL. When I was going through the Install Pre-requisites section on my Windows 10 system, all was well until I ran yarn start. I received the following error:
Error Message: 'openssl' is not recognized as an internal or external command
You can see more detail in the screenshot below.

Turns out that I did not have OpenSSL installed on this machine...
What I did to resolve my issue:
C:\Program Files\OpenSSL-Win64"C:\Program Files\OpenSSL-Win64\bin\openssl.exe"req -newkey rsa:2048 -new -nodes -x509 -days 3650 -keyout key.pem -out cert.pem -subj '/CN=www.mydom.com/O=My Company Name LTD./C=US' - (not sure if this command is different per user)yarn startSee successful example below:

I hope this information was helpful and not redundant. I am new to open source and appreciate the documentation that is available to help me get started very much!
Just wanted to let you know you are not alone. I ran into this exact issue.
I 'solved' this a slightly different way:
openssl req -newkey rsa:2048 -new -nodes -x509 -days 3650 -keyout key.pem -out cert.pem -subj '/CN=www.mydom.com/O=My Company Name LTD./C=US' (literally copied and pasted from webpack.js into my powershell prompt)yarn startJust figured I would add this for anyone not wanting to 'install' OpenSSL for just one thing (especially since you either have to compile your own or trust a third party to get it).
This is great info! We鈥檒l get the readme updated.
My copy of Git for Windows came with OpenSSL and with it added to the environment path, which is why I didn't run into any of these pain points.
I peeked and there doesn't seem to be a node package we can globally install to add OpenSSL, unfortunately.
@glyphstalker and @48klocs, thanks for your input! I didn't actually think to look there and none of the forums discussing 'how to install' it mentioned that either. After checking, it turns out that I did, in fact, have openssl.exe in that same git\usr location. From that, I think the issue then ultimately is that my windows Path didn't know about it.
Cheers!
Casey