JS新设置，删除重复项不区分大小写？ [英] JS new set, remove duplicates case insensitive?

问题描述

var arr = ['verdana', 'Verdana', 2, 4, 2, 8, 7, 3, 6];
result =  Array.from(new Set(arr));

console.log(arr);
console.log(result);

我想删除任何重复的不区分大小写的
所以预期的结果应该是

i want to remove any duplicates case-insensitive so the expected result should be

['Verdana'，2,4,8,7,3,6]

['Verdana', 2, 4, 8, 7, 3, 6]

但它似乎不起作用...

but it doesn't seem to work...

推荐答案

JavaScript比较器是大小写敏感。对于字符串，您可能需要先清理数据：

JavaScript comparator is case sensitive. For strings you may need to clean up the data first:

var arr = ['verdana', 'Verdana', 2, 4, 2, 8, 7, 3, 6]
  .map(x => typeof x === 'string' ? x.toLowerCase() : x);
result =  Array.from(new Set(arr));
// produces ["verdana", 2, 4, 8, 7, 3, 6];

---

或者，您可以使用 reduce（）使用自定义嵌套比较逻辑。 下面的实现比较忽略大小写的项目，但对于相等的字符串，它选择第一次出现，无论它的大小写是什么：

---

Alternatively, you may use reduce() with a custom nested comparing logic. The implementation below compares the items ignoring the case, but for "equal" strings it picks the first occurrence, regardless what its "casing" is:

'verdana', 'Moma', 'MOMA', 'Verdana', 2, 4, 2, 8, 7, 3, 6]
  .reduce((result, element) => {
    var normalize = function(x) { return typeof x === 'string' ? x.toLowerCase() : x; };

    var normalizedElement = normalize(element);
    if (result.every(otherElement => normalize(otherElement) !== normalizedElement))
      result.push(element);

    return result;
  }, []);
// Produces ["verdana", "Moma", 2, 4, 8, 7, 3, 6]

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