How do you group a set of data according to a particular field?

for example, I have a set of data

[
  {
    "time": "2018-03-01",
    "data": 1,
  },
  {
    "time": "2018-02-02",
    "data": 2,
  },
  {
    "time": "2018-01-01",
    "data": 3,
  },
  {
    "time": "2017-12-01",
    "data": 4,
  }, 
  {
    "time": "2017-11-02",
    "data": 5,
  }, 
  {
    "time": "2016-10-01",
    "data": 6,
  },
  {
    "time": "2016-9-01",
    "data": 7,
  }    
]

the actual business scenario is to group this set of data into groups of 5 items, but these 5 items are also divided into groups according to their dates and years

for example, the result of the above seven items is:

[
  {
    section: 1,
    sectionDatas: [
      {
        date: "2018",
        datas: [
          {
            "time": "2018-03-01",
            "data": 1,
          },
          {
            "time": "2018-02-02",
            "data": 2,
          },
          {
            "time": "2018-01-01",
            "data": 3,
          }
        ]
      },
      {
        date: "2017",
        datas: [
          {
            "time": "2017-12-01",
            "data": 4,
          }, 
          {
            "time": "2017-11-02",
            "data": 5,
          }
        ]
      }
    ]
  },
  {
    section: 2,
    sectionDatas: [
      {
        date: "2016",
        datas: [
          {
            "time": "2016-10-01",
            "data": 6,
          },
          {
            "time": "2016-9-01",
            "data": 7,
          } 
        ]
      }
    ]
  } 
]

how to write this algorithm. Ask for advice

var arr = new Object data.forEach(function(d){ var year = new Date(d.time).getFullYear() if(arr[year]){ arr[year].push(d) }else{ arr[year] = [d] } }) provides an idea. If you modify it, you should be able to use .