fearNotLetter("abce")
should return "d".
testString: assert.deepEqual(fearNotLetter('abce'), 'd');
- text: fearNotLetter("abcdefghjklmno")
should return "i".
testString: assert.deepEqual(fearNotLetter('abcdefghjklmno'), 'i');
- text: fearNotLetter("stvwx")
should return "u".
testString: assert.deepEqual(fearNotLetter('stvwx'), 'u');
- text: fearNotLetter("bcdf")
should return "e".
testString: assert.deepEqual(fearNotLetter('bcdf'), 'e');
- text: fearNotLetter("abcdefghijklmnopqrstuvwxyz")
should return undefined.
testString: assert.isUndefined(fearNotLetter('abcdefghijklmnopqrstuvwxyz'));
```