js字符串首字符无法用s[0]-32将小写转化为大写？

Question

function normalize(arr) {arr = arr.map((x)=>x.toLowerCase());arr = arr.map((x)=>{    console.log(typeof x[0]);    x[0] = x[0]-32;    //将首字符变大写    console.log(x[0]);return x});return arr;                        }normalize(['adam', 'LISA', 'barT']).toString();C里经常用S[0] = S[0] +/- 32来转换大小写。js似乎不行？

Answer 1

应该是32吧，js中的字符串不是字符数组

function normalize(arr) {

    arr = arr.map((x) => x.toLowerCase());

    arr = arr.map(x => String.fromCharCode(x.charCodeAt(0) & ~32) + x.substring(1));

    return arr;

}