littleomie

// let input = 'ECMU465749'; // 6
let input = 'GVTU300038'; // 9

function getCheckDigit(input) {
    const char_map = {
        'A': 10, 'B': 12, 'C': 13, 'D': 14, 'E': 15, 'F': 16, 'G': 17,
        'H': 18, 'I': 19, 'J': 20, 'K': 21, 'L': 23, 'M': 24, 'N': 25,
        'O': 26, 'P': 27, 'Q': 28, 'R': 29, 'S': 30, 'T': 31, 'U': 32,
        'V': 34, 'W': 35, 'X': 36, 'Y': 37, 'Z': 38
    };