mutation.rb

a = [{ slug: "foo"}, { slug: "bar" }]
b = a.sort_by { |e| e[:slug] }
a.push({ slug: "baz" })



result_1 = b.find { |e| e[:slug] == "baz" }


# Predict which branch executes
if (result_1.nil?)
  p "Elements pushed into array a DO NOT appear in array b"
else
  p "Elements pushed into array a DO appear in array b"
end

foo = b.find { |e| e[:slug] == "foo" }
foo[:marked] = true
result_2 = a.find { |e| e[:marked] }

# Predict which branch executes
if (result_2.nil?)
  p "Mutating one array's elements HAS NO effect on the other's"
else
  p "Mutating one array's elements CAN HAVE an effect on the other"
end