30-seconds-of-code/snippets/reduceWhich.md

reduceWhich

Return minimum / maximum value of a array, after applying the provided / defaulted function to set comparing rule. Use Array.reduce() with the first arguments and pass the above comparator function to Array.reduce() when running.

const reduceWhich = (arr, comparator = (a, b) => a - b) => arr.reduce(function (a, b) {
    return comparator(a, b) >= 0 ? b : a;
});

reduceWhich([1, 3, 2]); // 1

reduceWhich([1, 3, 2], (a, b) => b - a); // 3

reduceWhich([{name: 'Tom', age: 12}, {name: 'Jack', age: 18}, {name: 'Lucy', age: 9}], (a, b) => a.age - b.age) // {name: "Lucy", age: 9}