Dayofweek - en96321

test.js

// 修改前
function solution(S, K) {
    const d = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
    const nowDat = d.findIndex(item => item === S)
    const add = K % 7 
    if (add <= 6 - nowDat) {
        return d[nowDat + add]
    }

    return d[add - (6 - nowDat + 1)] 
    // write your code in JavaScript (Node.js 8.9.4)
}


// 修改後
function solution (S, K) {
  const dat = ['Mon', 'Tue', 'Wed', 'Sur', 'Fri', 'Sat', 'Sun']
 
  const nowDat = dat.findIndex(d => d === S)
  return dat[(nowDat + K) % 7]
}