How to group or merge this array of objects in javascript?

Question

I have an array of objects like below for example.

{name: \"Mc Donald\", quantity: 4, maleCount: 1, femaleCount: 0}
{name: \"KFC\", quantity: 9, maleCou         


        

Answer 1

Lodash makes your life easy.

_.map(_.groupBy(yourArrayHere, 'name'), (groupMembers, groupKey) => {
    let sumObject = {name: groupKey};

    _.forEach(['quantity', 'maleCount', 'femaleCount'], (property) => {
        sumObject[property] = 0;
        _.forEach(groupMembers, (member) => {
            sumObject[property] += member[property];
        });
    });

    return sumObject;
});