arrayManipulator

function arrayManipulator(array,comands) {



    for(let i=0;i<comands.length;i++) {
        let action = comands[i].split(` `);


       if(action[0] === `add`) {
           action.shift();
        array = add(array,action)
       } else if( action[0] === `contains`) {
        action.shift();
        console.log(array.indexOf(Number(action[0])))
       } else if(action[0]=== `addMany`) {
        action.shift();
        array = addMany(array,action)
       } else if( action[0] === `remove`) {
        action.shift();
        array = remove(array,action);
       } else if(action[0] === `shift`) {
        action.shift();
        array = shft(array,action);
       } else if(action[0] === `sumPairs`) {

        array = sumPair(array);
       } else if(action[0] === `print`) {

        break;
       }


    }

    return `[ ${array.join(`, `)} ]`

    function add(arr,action) {

        arr.splice(action[0],0,Number(action[1]))
        return arr;

    }


    function addMany(arr,action) {

      let  index = action.shift()

        for(let i=0;i<action.length;i++) {
            arr.splice(index++,0,Number(action[i]))
        }
        return arr;





    }

    function remove(arr,action) {
       let  index = action[0]
        arr.splice(Number(index),1)
        return arr;
    }

    function shft(arr,index) {

        for(let i=0;i<index;i++) {
            arr.push(arr[i]);
            arr.shift(arr[i]);

        }

        return arr
    }

    function sumPair(arr) {
        let output = []
       while(arr.length>0) {
           let a = arr.shift() || 0;
           let b = arr.shift() || 0;
           output.push(a+b)
       }
       return output;
        }



}
arrayManipulator([1, 2, 3, 4, 5],[`addMany 5 9 8 7 6 5`,`contains 15`,`remove 3`,`shift 1`,`print`]);