JavaScript native groupBy reduce

Question

I am using JavaScript native reduce, however I want to slightly change in the grouping to get my desired result. I have an array as follows:

const people = [
          


        

Answer 1

Try this. I use Array.prototype.forEach and Array.prototype.push

const people = [
  {name: "John", age: 23, city: "Seattle", state: "WA"},
  {name: "Mark", age: 25, city: "Houston", state: "TX"},
  {name: "Luke", age: 26, city: "Seattle", state: "WA"},
  {name: "Paul", age: 28, city: "Portland", state: "OR"},
  {name: "Matt", age: 21, city: "Oakland", state: "CA"},
  {name: "Sam", age: 24, city: "Oakland", state: "CA"}
];
var arranged=[];
people.forEach(function(e){
    var exist=false;
    arranged.forEach(function(e1){
        if(e1.state===e.state){
            exist=true;
            e1.persons.push({name:e.name,age:e.age});
        }
    });
    if(!exist){
        arranged.push({state:e.state,city:e.city,persons:[{name:e.name,age:e.age}]}); 
     }
});
console.log(arranged);