cellCoordsFromCellId function
Returns the coordinates from a cell name.
"A1" returns 1, 1
and the "B3" return 2, 3
.
Implementation
List cellCoordsFromCellId(String cellId) {
var letters = cellId.runes.map(_letterOnly);
var lettersPart =
utf8.decode(letters.where((rune) => rune > 0).toList(growable: false));
var numericsPart = cellId.substring(lettersPart.length);
var x = lettersToNumeric(lettersPart);
var y = int.parse(numericsPart);
return [x, y];
}