Check if array is empty in Bash

Supposing your array is $errors, just check to see if the count of elements is zero.

if [ ${#errors[@]} -eq 0 ]; then
    echo "No errors, hooray"
else
    echo "Oops, something went wrong..."
fi

I generally use arithmetic expansion in this case:

if (( ${#a[@]} )); then
    echo not empty
fi