JS新设置，删除重复项不区分大小写？

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-insensitiveso the expected result should be

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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