/**
* @param {string} s
* @return {string[]}
*/
var cellsInRange = function(s) {
const result = []
const startIdx = s[0].charCodeAt()
const endIdx = s[3].charCodeAt()
const startRow = +s[1]
const endRow = +s[4]
for(let i=startIdx; i<=endIdx; i++){
for(let j=startRow; j<=endRow; j++) {
result.push(String.fromCharCode(i)+j)
}
}
return result
};