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

You can use the function reduce to group and build the desired output.

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"}]

const result = Object.values(people.reduce((a, {name, age, city, state}) => {
  var key = [city, state].join('|');
  (a[key] || (a[key] = {city, state, persons: []})).persons.push({name, age});
  return a;
}, {}));

console.log(result);

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