This was the task (I don't know the exact wordings anymore):

You get a string with operation as input:

1. if it is a number push it to stack
2. if it is "DUP", then duplicate the one one top and push it to the stack
3. if it is "POP" then remove the one on top
4. if it is "+" add the two numbers on top of the stack and replace both with the result of the addition
5. if it is "-" then minus the two numbers on top (the second minus the first) of the stack and replace both with the result of the subtraction
6. if an error occurs, e.g. not enough numbers to add/subtract/pop, then return -1

Examples:

Input: "3 DUP 5 - -"
Output: -1

Input: "13 DUP 4 POP 5 DUP + DUP + -"
Output: 7

Input: "5 6 + -"
Output: -1

My solution:

function solution(S) {
    if (!S.length) {
        return -1;
    }
    const stack = new Array();
    const push = n => stack.push(Number(n));
    const pop = () => {
        if (!stack.length) {
            throw new Error('empty');            
        }
        return stack.pop();
    }
    const duplicate = () => {
        try {
            const dup = pop();
            push(dup);
            push(dup);            
        } catch(e) {
            throw new Error(e);    
        }
    };
    const add = () => {
        try {
            const sum1 = pop();
            const sum2 = pop();
            push(sum1 + sum2);            
        } catch(e) {
            throw new Error(e);    
        }
    };
    const minus = () => {
        try {
            const min1 = pop();
            const min2 = pop();
            push(min1 - min2);
        } catch(e) {
            throw new Error(e);    
        }
    };
    const ops = {
        "DUP": duplicate,
        "POP": pop,
        "+": add,
        "-": minus,
    };

    const input = S.split(' ');
    input.forEach(x => {
        if (!isNaN(x)) {
            push(x);
        } else {
            try {
                const sanitzedX = x.toUpperCase();
                if (!ops[sanitzedX]) {
                    return -1;
                }
                ops[sanitzedX]();
            } catch(e) {
                return -1;
            }
        }
    });
    try {
        return pop();
    } catch(e) {
        return -1;
    }
}

console.log(solution("3 DUP 5 - -"));
console.log(solution("13 DUP 4 POP 5 DUP + DUP + -"));
console.log(solution("5 6 + -"));