反转字符串

let a = `sadfsafdsdfsefdsfc`
function reverse1(a){
    return a.split('').reverse().join('')
}
let t = ()=> +new Date()
let t1 = t();
console.log(reverse1(a));
let t2 = t();
console.log(t2-t1,'t2-t1');
function reverse(a){
    if (a.length === 1 ) {
        return a[0]
    }
    return a[a.length-1]+=reverse(a.slice(0,a.length-1))
}
let t3 = t();

console.log(reverse(a));
let t4 = t();
console.log(t4-t3,'t4-t3');