function containsRepeatingLetter(str) { let arr = str.split(''); return arr.some((element,index)=>{ return element==arr[index+1]&&((element>'a'&&element<'z')||(element>'A'&&element<'Z')) }) } containsRepeatingLetter('bookkeeping')
function containsRepeatingLetter(str) { let r = str.match(/[a-zA-Z]/g); return r.length !== new Set(r).size }
function containsRepeatingLetter(str) { let obj = {}; for (let i = 0; i < str.length; i++) { // 包含a-zA-Z才统计 if (/[a-zA-Z]/.test(str[i])) { if (obj[str[i]]) { return true; } else { obj[str[i]] = 1; } } } return false; }