Group dictionary (array of objects) based on one object (key)

Group dictionary (array of objects) based on one object (key)

<div style="background:green;" id="one"></div>


<script>
Array.prototype.groupBy = function(prop) {
  return this.reduce(function(groups, item) {
    const val = item[prop]
    groups[val] = groups[val] || []
    groups[val].push(item)
    return groups
  }, {})
}

const events = [
  { time: '12:00', location: 'mall' },
  { time: '9:00', location: 'store' },
  { time: '9:00', location: 'mall' },
  { time: '12:00', location: 'store' },
  { time: '12:00', location: 'market' },
]

const groupedByTime = events.groupBy('time')

document.getElementById("one").innerHTML = JSON.stringify(groupedByTime, null, 2);

</script>