SOURCE

let arr = ["nap", "teachers", "cheaters", "PAN", "ear", "era", "hectares"];

function aclean(arr) {
   let map = new Map()
   arr.forEach(item => {
       let sorted = item.toLowerCase().split('').sort().join('')
       map.set(sorted, item)
   })
   console.log(map.values())
   return Array.from(map.values())
}

console.log(aclean(arr))

/**
function aclean(arr) {
  let map = new Map();

  for (let word of arr) {
    // 将单词 split 成字母，对字母进行排序，之后再 join 回来
    let sorted = word.toLowerCase().split('').sort().join(''); // (*)
    map.set(sorted, word);
  }

  return Array.from(map.values());
}

let arr = ["nap", "teachers", "cheaters", "PAN", "ear", "era", "hectares"];

console.log( aclean(arr) );
**/