Unable to access inner JSON value in JSON array - Typescript(Using Angular 8)

Question

I am trying to use the group by function on a JSON array using the inner JSON value as a key as shown below. But unable to read the inner JSON value. Here is my JSON array.

NotificationData = [ 
   { 
      "eventId":"90989",
      "eventTime":"2019-12-11T11:20:53+04:00",
      "eventType":"yyyy",
      "event":{ 
         "ServiceOrder":{ 
            "externalId":"2434",
            "priority":"1"
         }
      }
   },
   { 
      "eventId":"6576",
      "eventTime":"2019-12-11T11:20:53+04:00",
      "eventType":"yyyy",
      "event":{ 
         "ServiceOrder":{ 
            "externalId":"78657",
            "priority":"1"
         }
      }
   }
]

GroupBy Logic:

const groupBy = (array, key) => {
  return array.reduce((result, currentValue) => {
    (result[currentValue[key]] = result[currentValue[key]] || []).push(
      currentValue
    );
    return result;
  }, {});
};

const serviceOrdersGroupedByExternalId = groupBy(this.NotificationData, 'event.ServiceOrder.externalId');
                                 //this line of code is not working as
                             // it is unable to locate the external id value.

Desired output

{ "2434":[{
     "eventId":"90989",
     "eventTime":"2019-12-11T11:20:53+04:00",
     "eventType":"yyyy",
     "event":{
        "ServiceOrder":{ "priority":"1" }
     } 
  }],
  "78657":[{
     "eventId":"6576",
     "eventTime":"2019-12-11T11:20:53+04:00",
     "eventType":"yyyy", 
     "event":{
        "ServiceOrder":{ "priority":"1" }
     }
  }]
}

{ "2434":[ { "eventId":"90989", "eventTime":"2019-12-11T11:20:53+04:00", "eventType":"yyyy", "event":{ "ServiceOrder":{ "priority":"1" } } }], "78657":[ { "eventId":"6576", "eventTime":"2019-12-11T11:20:53+04:00", "eventType":"yyyy", "event":{ "ServiceOrder":{ "priority":"1" } } }] } — Sneha Aitha, Dec 19 '19 at 05:50

score 1 · Answer 1 · answered Dec 19 '19 at 06:16

1

Does this solves your purpose?

let group = NotificationData.reduce((r, a) => {
  let d = r[a.event.ServiceOrder.externalId] = [...r[a.event.ServiceOrder.externalId] || [], a];
  return r;
 }, {});
 console.log(group);

answered Dec 19 '19 at 06:16

Mridul

1,320
1
5
19

Thank you so much. It works as expected. Could you please brief me about the code since I am a beginner? – Sneha Aitha Dec 19 '19 at 06:26
You are welcome. For better understanding please visit here https://www.consolelog.io/group-by-in-javascript/ – Mridul Dec 19 '19 at 06:35

score 1 · Answer 2 · answered Dec 19 '19 at 06:31

Try like this:

result = {};

constructor() {
  let externalIds = this.NotificationData.flatMap(item => item.event.ServiceOrder.externalId);

  externalIds.forEach(id => {
      var eventData = this.NotificationData.filter(
        x => x.event.ServiceOrder.externalId == id
      ).map(function(item) {
        delete item.event.ServiceOrder.externalId;
        return item;
      });
      this.result[id] = eventData;
  });
}

Working Demo

Unable to access inner JSON value in JSON array - Typescript(Using Angular 8)

GroupBy Logic:

Desired output

2 Answers2