Ето още по-оптимизиран:

function solve(arr) {

    const degrees = arr[0];
    const partOfDay = arr[1];
    let outfit, shoes;

    if (partOfDay == "Morning") {
        if (degrees <= 18) {
            outfit = "Sweatshirt";
            shoes = "Sneakers";
        }
        else if (degrees <= 24) {
            outfit = "Shirt";
            shoes = "Moccasins";
        } else {
            outfit = "T-Shirt";
            shoes = "Sandals";
        }
    } else if (partOfDay == "Afternoon") {
        if (degrees <= 18) {
            outfit = "Shirt";
            shoes = "Moccasins";
        } else if (degrees <= 24) {
            outfit = "T-Shirt";
            shoes = "Sandals";
        } else {
            outfit = "Swim Suit";
            shoes = "Barefoot";
        }
    } else {
        outfit = "Shirt";
        shoes = "Moccasins";
    }
    console.log(`It's ${degrees} degrees, get your ${outfit} and ${shoes}."`);
}