Javascript - iterating and deleting from object

Question

I have the following object

familyData: [
                    { man: 1, woman:10, daughter:6, son:3 },
                    { man: 4 woman:5, daughter:5, son:2 },
                    { man: 1, woman:1, daughter:1, son:1 },
                    { man: 1, woman:1, daughter:1, son:1 },
                    { man: 1, woman:1, daughter:1, son:1 },
                    ],

What I am trying to do is delete 1 from a each index, however the number of subtractions is user submitted.

let me explain...

If the user inserts a 2. 1 will be taken away from the first 2 indexes in the object

 { man: 0, woman: 9, daughter:6, son:3 },
 { man: 3 woman:4, daughter:5, son:2 },

If the user inserts a 4. 1 will be taken away from the first 4 indexes in the object

 { man: 0, woman: 9, daughter:5, son:2 },
 { man: 3 woman:4, daughter:4, son:1 },

I have tried a variety of for and do-while loops but cannot seem to nail it.

Answer 1

Try:

var indexes = 0;
for (var i=0; i<familyData.length; ++i) {
    for (var key in familyData[i]) {
        if (++indexes < 4 && familyData[i][key]) {
            familyData[i][key]--;
        }
    }
}