JavaScript​ program that​ displays​ a list​ of​ names​ according​ to​ ​the sports​ group

let a = 
[
    {
        Name: 'Ravindra',
        Sports: ['Chess', 'Cricket'],  
    },
    {
        Name: 'Ravi',
        Sports: ['Cricket', 'Football'],
    },
    {
        Name: 'Rishabh',
        Sports: ['Table-Tennis', 'Football'],
    },
]

const result = a.reduce((groupedSports, person) => {
    const Sports = person.Sports
    if(groupedSports[Sports]== null) groupedSports[Sports] = []
    groupedSports[Sports].push(person)
    return groupedSports
}, {})
    console.log(result)

expected output

// Chess:​ ​ [‘Ravindra’] }, { Cricket:​ [‘Ravindra’,'Ravi'] }, { Football:​ ​ [‘Ravi’,​ ​ ‘Rishabh’] }, { Table-Tennis:​ ​ [‘Rishabh']}]

I was able to group according to the Sports, but sports is an array. how do i group it by individual sports?

>Solution :

You can iterate over all sports and check if it already exists, if not, spread all current entries and add the new persons Name to the array.

let a = [{
    Name: 'Ravindra',
    Sports: ['Chess', 'Cricket'],
  },
  {
    Name: 'Ravi',
    Sports: ['Cricket', 'Football'],
  },
  {
    Name: 'Rishabh',
    Sports: ['Table-Tennis', 'Football'],
  },
]

const result = a.reduce((groupedSports, person) => {
  person.Sports.forEach((sport) => {
    groupedSports[sport] = groupedSports?.[sport]
      ? [...groupedSports[sport], person.Name]
      : [person.Name];
  });
  return groupedSports;
}, {});

console.log(result)