Filter all item with lowest nearest value in array using javascript

January 10, 2024

I have a sorted array is

array = [
    { id: 1, orderTotal: 50000 },
    { id: 3, orderTotal: 50000 },
    { id: 2, orderTotal: 100000 },
    { id: 4, orderTotal: 200000 },
]

I want find all order total if nearest with a total price.

This is my code

const getNearestOrderValue = (arr, totalPrice) => {
    let nearestItem = [];
    let maxSmaller = 0;
    
    for (const item of arr) {
        if (item?.orderTotal <= totalPrice && item?.orderTotal >= maxSmaller) {
          maxSmaller = item?.orderTotal;
          nearestItem.push(item);
        }
    }
    return nearestItem;
}

if total price = 80000, my code return correct result is

[
   { id: 1, orderTotal: 50000 },
   { id: 3, orderTotal: 50000 },
]

but if total price is 120000, my code result is

[
  { id: 1, orderTotal: 50000 },
  { id: 3, orderTotal: 50000 },
  { id: 2, orderTotal: 100000 }
]

I want result is

[
 { id: 2, orderTotal: 100000 }
]

How can i fix this getNearestOrderValue function to response correct? I am looking forward to receive help from anyone.

>Solution :

You just have to reset your output array when you find a closer value. There is no need to loop 2*n times and definitely no need to loop n^2 times.

const array = [
    { id: 1, orderTotal: 50000 },
    { id: 3, orderTotal: 50000 },
    { id: 2, orderTotal: 100000 },
    { id: 4, orderTotal: 200000 },
];

const getNearestOrderValue = (arr, totalPrice) => {
    let nearestItem = [];
    let maxSmaller = 0;
    
    for (const item of arr) {
        if (item?.orderTotal <= totalPrice && item?.orderTotal >= maxSmaller) {
          if (item?.orderTotal > maxSmaller) {
            maxSmaller = item?.orderTotal;
            nearestItem = [];
          }
          nearestItem.push(item);
        }
    }
    return nearestItem;
}

console.log(getNearestOrderValue(array, 120000));