Convert from excel column names to a index (1 based)

Excel column name to number.js

function colNum(name = '') {
  const val = (c) => c.charCodeAt(0) - 'A'.charCodeAt(0) + 1
  return name.split('')
    .reduce((acc, v) => val(v) + acc * val('Z'), 0)
}

colNum('A')  === 1
colNum('Z')  === 26

colNum('AA') === 27
colNum('AZ') === 52
colNum('ZZ') === 702

colNum('AAA') === 703
colNum('AZA') === 1353
colNum('ZZZ') === 18278

function col(name) {
	let a = 'A'.charCodeAt(0)
	let idx = 0
	for (let i = 0; i < name.length; i++) {
		idx *= 26
		idx += name.charCodeAt(i) - a + 1
	}
	return idx
}