Javascript:从字符串中删除原始字符和重复字符

Question

我需要的是删除原始字符及其重复字符，无论它是小写还是大写。如果它的大写或小写也应该保留

这是我当前的代码，但如果字符串是大写然后是小写，它无法过滤。

const removeDuplicateChar = s => s
  .split('')
  .filter( ( cur, index, self ) => self.lastIndexOf( cur ) === self.indexOf( cur ) )
  .join('')

Actual Output

'services' becomes 'rvic'
'stress' becomes 'tre'
'ServicEs' becomes 'ServicEs'
'streSs' becomes 'treS'
'DeadSea' becomes 'DdS'

Expected Output

'services' should be 'rvic'
'stress' should be 'tre'
'ServicEs' should also be 'rvic'
'streSs' should also be 'tre'
'DeadSea' becomes 'S'

Answer 1

这应该更快，因为循环中没有 indexOf:

const removeDuplicateChar = s => {
  let counts = Array.from(s.toLowerCase()).reduce(
    (counts, char) => counts.set(char, (counts.get(char) || 0) + 1) && counts,
    new Map());
  return Array.from(s).filter(letter =>
    counts.get(letter.toLowerCase()) == 1
  ).join('');
}

['services', 'stress', 'ServicEs', 'streSs', 'DeadSea'].forEach(word =>
  console.log(word, removeDuplicateChar(word))
)