KotlinQuiz2.kt

// implement search function that can be filter by name,priceRange or category
fun List<Product>.search(name: String? = null,
                         priceRange: Pair<Double, Double>? = null,
                         categoryId: String? = null): List<Product> = TODO("Make it happen")

Admin solution

fun List<Product>.search(name: String? = null,
                         priceRange: Pair<Double, Double>? = null,
                         categoryId: String? = null): List<Product> = this
        .let { filteredList -> if (name != null) filteredList.filter { it.name.startsWith(name) } else filteredList }
        .let { filteredList -> if (priceRange != null) filteredList.filter { it.price in priceRange.first..priceRange.second } else filteredList }
        .let { filteredList -> if (categoryId != null) filteredList.filter { it.category.id == categoryId } else filteredList }