let a = [ { Name: 'Josh', Subject: ['Biology', 'Chemistry'], }, { Name: 'James', Subject: ['Chemistry', 'Physics'], }, { Name: 'Mary', Subject: ['Physics', 'Mathematics'], }, ] const result = a.reduce((groupedSubject, person) => { const Subject = person.Subject if(groupedSubject[Subject]== null) groupedSubject[Subject] = [] groupedSubject[Subject].push(person) return groupedSubject }, {}) console.log(result)También debe iterar la matriz Sports .
const data = [{ Name: 'Ravindra', Sports: ['Chess', 'Cricket'] }, { Name: 'Ravi', Sports: ['Cricket', 'Football'] }, { Name: 'Rishabh', Sports: ['Table-Tennis', 'Football'] }], result = data.reduce((groupedSports, person) => { person.Sports.forEach(sport => { groupedSports[sport] ??= []; groupedSports[sport].push(person.Name); }) return groupedSports; }, {}); console.log(result); .as-console-wrapper { max-height: 100% !important; top: 0; }Puede iterar sobre todos los deportes y verificar si ya existe, si no, distribuir todas las entradas actuales y agregar el Name de la nueva persona a la matriz.
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)