Array search

let input = [
    '4,3,2,7,8,2,3,1',
];

let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);

let list = gets();
let arrayList = list.split(',').map(Number);

let arrayListSorted = arrayList.sort(function(a, b){return a - b});

let removeDuplicates = [];
for (let n = 0; n < arrayListSorted.length; n++) {
    if (removeDuplicates.includes(arrayListSorted[n]) === false) {
        removeDuplicates.push(arrayListSorted[n]);
    }
}

let arrayNumbers = [];
for (let i = 1; i <= arrayListSorted.length; i++) {
    arrayNumbers.push(i);
}

let arraySearch = [];
if (removeDuplicates.length === 1) {
    for (let j = 0; j < arrayNumbers.length; j++) {
        if (removeDuplicates[0] !== arrayNumbers[j]) {
            arraySearch.push(arrayNumbers[j]);
        }
    }
} else if (removeDuplicates.length > 1) {
    for (let j = 0; j < removeDuplicates.length; j++) {
        if (removeDuplicates[j] !== arrayNumbers[j]) {
            arraySearch.push(arrayNumbers[j]);
        }
    }
}

let arraySearchString = arraySearch.join(',');
console.log(arraySearchString);