SOURCE

function getNums(ints, s) {
    let arr = []
    ints.forEach((val, index) => {
        const num = s - val
        const lastIndex = ints.lastIndexOf(num)
        if (lastIndex > -1 && lastIndex !== index) {
            if (!arr.length || lastIndex - index < arr[2]) {
                arr = [index, lastIndex, lastIndex - index]
            }
        }
    })
    if (arr.length) {
        return [ints[arr[0]], ints[arr[1]]]
    } else {
        return undefined
    }
}
console.log(getNums([10,5,2,3,7,5], 10))