Function maxBy

maxBy<T>(
arr: readonly T[],
iteratee: (item: T) => string | number,
): T | undefined
Returns the first element of an array with the maximum value according to an iteratee function.

The iteratee is invoked for each element, and the element with the largest resulting value is returned. If multiple elements tie for the maximum, the first one encountered is kept. If the array is empty, undefined is returned.

根据迭代函数返回数组中对应值最大的第一个元素。

对每个元素调用迭代函数，返回结果值最大的那个元素。若多个元素并列最大，则保留最先遇到的元素。若数组为空，返回 undefined。
Type Parameters
- T
  The type of elements in the array / 数组元素的类型
Parameters
- arr: readonly T[]
  The array to search. 要搜索的数组
- iteratee: (item: T) => string | number
  The function invoked per element, returning a number or string. 对每个元素调用的迭代函数，返回数字或字符串
Returns T | undefined
The element with the maximum value, or undefined if the array is empty. 值最大的元素，数组为空时返回 undefined
Remarks
O(n) time complexity - single pass through the array

O(n) 时间复杂度 - 单次遍历数组
Example
```
maxBy([{ n: 1 }, { n: 3 }, { n: 2 }], (u) => u.n)
// => { n: 3 }
```
Example
```
maxBy(['pear', 'apple', 'banana'], (s) => s)
// => 'pear'
```
- Defined in src/array/max-by.ts:38