Was looking at canjs5 earlier, and tried to install via the instructions.
I’ve got npm 6, but there’s a dependency in “can-connect” (must be related to canjs base) which requires npm 3 (only). This was set in 2016, and hasn’t been fixed. I have to wonder how people have been installing and using canjs in the last year or so… ?
I created a bug with canjs, but the ‘fix’ if you happen to get here searching for this bug…
npm install can@5 –save –engine-strict=false