the final quest - mid exam

function theFinalQuest(input){
    let wordsCollection = input.shift().split(' ');

    while(input.length > 0){
        let command = input.shift();

        if(command == 'Stop'){
            break;
        }

        let curCommand = command.split(' ')[0];

        switch(curCommand){
            case 'Delete' :
                let indexForDelite = Number(command.split(' ')[1]);
                wordsCollection = deliteCase(wordsCollection, indexForDelite);
                break;
            case 'Swap' :
                let firstWord = command.split(' ')[1];
                let secondWord = command.split(' ')[2];
                wordsCollection = swapCase(wordsCollection, firstWord, secondWord);
                break;
            case 'Put' :
                let wordPutCase = command.split(' ')[1];
                let indexPutCase = Number(command.split(' ')[2]);
                wordsCollection = putCase(wordsCollection, wordPutCase, indexPutCase);
                break;
            case 'Sort':
                wordsCollection = wordsCollection.sort((a, b) => b.localeCompare(a));
                break;
            case 'Replace' :
                let firstWordReplace = command.split(' ')[1];
                let secondWordReplace = command.split(' ')[2];
                wordsCollection = replaceCase(wordsCollection, firstWordReplace, secondWordReplace);
                break;

        }
    }

    console.log(wordsCollection.join(' '));

    function deliteCase(arr, index){
        if(index + 1 > 0 && index + 1 < arr.length){
            arr = arr.filter((x,y) => y != index + 1);
        }
        return arr;
    }

    function swapCase(arr, first, second){
        let firstSwap = second;
        let secondSwap = first;

        if(arr.includes(first) && arr.includes(second)){
            for(let i = 0; i < arr.length; i++){
                if(arr[i] == first){
                    arr[i] = firstSwap;
                } else if (arr[i] == second){
                    arr[i] = secondSwap;
                }
            }
        }
        return arr;
    }

    function putCase(arr, word, index){
        if(index - 1 > 0 && index - 1 < arr.length){
            arr.splice(index - 1,0,word);
        }
        return arr;
    }

    function replaceCase(arr, first, second){
        if(arr.includes(second)){
            for(let i = 0; i < arr.length; i++){
                if(i == arr.indexOf(second)){
                    arr[i] = first;
                }
            }
        }
        return arr;
    }
}