function generate_range_of_ASCII_values(ch_from, ch_to) {
let s = [...Array(ch_to.charCodeAt(0) - ch_from.charCodeAt(0) + 1).keys()].
map(i => i + ch_from.charCodeAt(0));
return s;
}
console.log(generate_range_of_ASCII_values('c', 'j'));
/*
run:
[99, 100, 101, 102, 103, 104, 105, 106]
*/