Javascript -计数对象数组中的重复项并将计数存储为新对象

var countObj = {};

for (var i = 0; i < objArray.length; i++) {
  var item = objArray[i];
  if (countObj[item]) {
    countObj[item]++;
  } else {
    countObj[item] = 1;
  }
}

var objArray = [1, 2, 3, 2, 1, 3, 4, 5, 4, 4, 4];
var countObj = {};

for (var i = 0; i < objArray.length; i++) {
  var item = objArray[i];
  if (countObj[item]) {
    countObj[item]++;
  } else {
    countObj[item] = 1;
  }
}

console.log(countObj);

{
  1: 2,
  2: 2,
  3: 2,
  4: 4,
  5: 1
}