Difference Cipher

It's time to send and receive secret messages.

Create a single function that takes a string or an array and returns a coded or decoded message.

The first letter of the string, or the first element of the array represents the Character Code of that letter. The next elements are the differences between the characters: e.g. A +3 --> C or z -1 --> y.

Examples

difCiph("Hello") ➞ [72, 29, 7, 0, 3]
// H = 72, the difference between the H and e is 29 (upper- and lowercase).
// The difference between the two l's is obviously 0.

difCiph([ 72, 33, -73, 84, -12, -3, 13, -13, -68 ]) ➞ "Hi there!"

difCiph("Sunshine") ➞ [83, 34, -7, 5, -11, 1, 5, -9]

Notes

The input of the function will always be a string or an array with numbers.