how to Group By Array in Angular 4 OR 5?

Question

i got this type of array, and i want to group by only one column (first_name) from whole array,

[
   {
     first_name: "Apurv",
     date: "2018-01-22",
     is_present: "1", 
   }
   {
     first_name: "Lucky",
     date: "2018-01-22",
     is_present: "0", 
   }
   {
     first_name: "Apurv",
     date: "2018-01-20",
     is_present: "0", 
   }
   {
     first_name: "Lucky",
     date: "2018-01-20",
     is_present: "1", 
   }
]

so how can i group by this array from "component"?

@AyushGupta i don't want to repeat "first_name", you can see in the above array first_name is repeated. — Apurv Chaudhary, Jan 22 '18 at 07:14
https://github.com/Chalarangelo/30-seconds-of-code#groupby. Note that this has absolutely nothing to do with Angular. It's a pure JavaScript question. — JB Nizet, Jan 22 '18 at 07:15
From both of the same name, do you want to show the first record? o there is a condition to pick from those two? — Nestor, Jan 22 '18 at 07:17
@Nestor i want both array record but want 'first_name' only one time. — Apurv Chaudhary, Jan 22 '18 at 07:23
https://stackoverflow.com/questions/14446511/what-is-the-most-efficient-method-to-groupby-on-a-javascript-array-of-objects — Eliseo, Jan 22 '18 at 07:25
Possible duplicate of [What is the most efficient method to groupby on a JavaScript array of objects?](https://stackoverflow.com/questions/14446511/what-is-the-most-efficient-method-to-groupby-on-a-javascript-array-of-objects) — Jota.Toledo, Jan 22 '18 at 08:10

score 11 · Accepted Answer · answered Jan 22 '18 at 07:50

var data = [
   {
     first_name: "Apurv",
     date: "2018-01-22",
     is_present: "1", 
   },
   {
     first_name: "Lucky",
     date: "2018-01-22",
     is_present: "0", 
   },
   {
     first_name: "Apurv",
     date: "2018-01-20",
     is_present: "0", 
   },
   {
     first_name: "Lucky",
     date: "2018-01-20",
     is_present: "1", 
   }
];

var groupByName = {};

data.forEach(function (a) {
    groupByName [a.first_name] = groupByName [a.first_name] || [];
    groupByName [a.first_name].push({ date: a.date, is_present: a.is_present });
});

console.log(groupByName);

how to Group By Array in Angular 4 OR 5?

1 Answers1

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