maxBy 
Finds the element in an array that has the maximum value when applying the getValue function to each element.
Signature 
typescript
function maxBy<T>(items: [T, ...T[]], getValue: (element: T) => number): T;
function maxBy<T>(items: T[], getValue: (element: T) => number): T | undefined;Parameters 
- items(- T[]): The array of elements to search.
- getValue(- (item: T) => number): A function that selects a numeric value from each element.
Returns 
(T): The element with the maximum value as determined by the getValue function.
Example 
typescript
maxBy([{ a: 1 }, { a: 2 }, { a: 3 }], x => x.a); // Returns: { a: 3 }
maxBy([], x => x.a); // Returns: undefined
maxBy(
  [
    { name: 'john', age: 30 },
    { name: 'jane', age: 28 },
    { name: 'joe', age: 26 },
  ],
  x => x.age
); // Returns: { name: 'john', age: 30 }
