How group multiple using lodash

Question

I have below array

const array = [
  {
    key: 'TSJUcgLGig2UOdjAzlqq4KW5GK6PKXHC2ndw40HYIss7EKsV6nJ',
    location: { lat: '22.7196', lng: '75.8577' },
    address: { city: 'NY', country: 'USA' },
    className: 'FourthActivity',
    deviceId: '1111111111111111'
  },
  { 
    key: 'TSJUcgLGig2UOdjAzlqq4KW5GK6PKXHC2ndw40HYIss7EKsV6nJ',
    location: { lat: '22.7196', lng: '75.8577' },
    address: { city: 'NY', country: 'USA' },
    className: 'FourthActivity',
    deviceId: '222222222222222'
  },
  {
    key: 'TSJUcgLGig2UOdjAzlqq4KW5GK6PKXHC2ndw40HYIss7EKsV6nJ',
    location: { lat: '22.7196', lng: '75.8577' },
    address: { city: 'Landon', country: 'UK' },
    className: 'FourthActivity',
    deviceId: '33333333333'
 }
]

I have to group it by using two properties inside the object i.e. address and className. How can I do this either with loadash or javascript?

expected output

[{
  address: { city: 'NY', country: 'USA' }, className: 'FourthActivity',
  count: 2,
  data: [{
    deviceId: 222222222222222,
  }, {
    deviceId: 1111111111111111,
  }]
}, {
  address: { city: 'Landon', country: 'UK' }, className: 'FourthActivity',
  count: 1,
  data: [{
    deviceId: 33333333333,
  }]
}]

I have tried this but doesn't work

var selectedVehicle = _.filter(array, 'address')

  const selectedVehicles = _.groupBy(selectedVehicle, function(item) {
  return item.makeCode;
})

console.log(selectedVehicles)

Where does `city: 'NY', country: 'USA' ` and `city: 'Landon', country: 'UK'` come from in your expected output? It's nowhere in your input. — CertainPerformance, Apr 10 '19 at 07:37

score 1 · Accepted Answer · answered Apr 10 '19 at 07:41

1

You can reduce into an object, creating { address, className, count: 0, data: [] } if it doesn't exist for the given address / className pair yet, and then get that object's values:

const array = [
  {
    key: 'TSJUcgLGig2UOdjAzlqq4KW5GK6PKXHC2ndw40HYIss7EKsV6nJ',
    location: { lat: '22.7196', lng: '75.8577' },
    address: { city: 'NY', country: 'USA' },
    className: 'FourthActivity',
    deviceId: '1111111111111111'
  },
  { 
    key: 'TSJUcgLGig2UOdjAzlqq4KW5GK6PKXHC2ndw40HYIss7EKsV6nJ',
    location: { lat: '22.7196', lng: '75.8577' },
    address: { city: 'NY', country: 'USA' },
    className: 'FourthActivity',
    deviceId: '222222222222222'
  },
  {
    key: 'TSJUcgLGig2UOdjAzlqq4KW5GK6PKXHC2ndw40HYIss7EKsV6nJ',
    location: { lat: '22.7196', lng: '75.8577' },
    address: { city: 'Landon', country: 'UK' },
    className: 'FourthActivity',
    deviceId: '33333333333'
 }
]
const output = Object.values(array.reduce((a, { address, className, deviceId }) => {
  const addressClassNameStr = JSON.stringify({ address, className });
  if (!a[addressClassNameStr]) {
    a[addressClassNameStr] = { address, className, count: 0, data: [] };
  }
  a[addressClassNameStr].count++;
  a[addressClassNameStr].data.push({ deviceId });
  return a;
}, {}));
console.log(output);

answered Apr 10 '19 at 07:41

CertainPerformance

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Nothing is perfect then your answer. Thanks a lot for the lightning fast answer. Wonder if this can be done using lodash? or this is the best way? – Profer Apr 10 '19 at 07:46
You could also start with it in Lodash by using the `groupBy` callback: `return JSON.stringify({ address, className });` (but it's so simple in plain JS, so no need for a library IMO) – CertainPerformance Apr 10 '19 at 07:52
Hi Can I sort the data using count? – Profer Apr 10 '19 at 09:25
Sure https://stackoverflow.com/questions/979256/sorting-an-array-of-javascript-objects-by-property – CertainPerformance Apr 10 '19 at 09:26
So I need use one more loop? Can it be done with above single one? – Profer Apr 10 '19 at 09:40
No, it's impossible in under `O(N log N)`, unfortunately – CertainPerformance Apr 10 '19 at 09:51

How group multiple using lodash

1 Answers1