add and remove elements

function  solve(arr1) {

    let arr2 = [];

    for (let i = 0; i < arr1.length; i++) {

        if (arr1[i] == 'add') {
            let number = i + 1;
            arr2.push(number);
        } else {
            arr2.pop();
        }
    }

    if (arr2.length > 0){
        for (let el of arr2) {
            console.log(el);
        }
    }
    else {
        console.log('Empty');
    }

}