Counting occurrences of particular property value in array of objects [duplicate]

Answer 1

You count

var arr = [
  {id: 12, name: 'toto'},
  {id: 12, name: 'toto'},
  {id: 42, name: 'tutu'},
  {id: 12, name: 'toto'}
]

function getNbOccur(id, arr) {
  var occurs = 0;
  
  for (var i=0; i