It's because it is not proven that element with the index 1 exists. Even TypeScript enforces bounds checking these days.
As for the first one - as i understand, this will spoil the original array, as it is assigned by reference; so by writing the string into `numbersOrStrings`, you also write it into `numbers`, thus violating the type.
There's also Mailtrap http://mailtrap.io/ that prevents test emails from getting to real addresses, and collects them on a server where they could be viewed by every member of the team.
I'm a remote Ruby developer. Most of our team is on-site.
My main problem is: online communication makes discussion much more complicated than face-to-face, so you don't contribute as much ideas when people brainstorm or otherwise solve creative problems. If you have a lot of ideas, that can be depressing.
I visit the office several times a year, mostly to share thoughts and socialize.
[1] https://mailtrap.io.