Sum object properties

importance: 5

We have an object storing salaries of our team:

let salaries = {
 John: 100,
 Ann: 160,
 Pete: 130
}

Write the code to sum all salaries and store in the variable sum. Should be 390 in the example above.

If salaries is empty, then the result must be 0.

let salaries = {
 John: 100,
 Ann: 160,
 Pete: 130
};
let sum = 0;
for (let key in salaries) {
 sum += salaries[key];
}
alert(sum); // 390