JAVASCRIPT

groupby angular

content_copyopen_in_new
import { of } from 'rxjs';
import { mergeMap, groupBy, reduce } from 'rxjs/operators';
 
of(
  {id: 1, name: 'JavaScript'},
  {id: 2, name: 'Parcel'},
  {id: 2, name: 'webpack'},
  {id: 1, name: 'TypeScript'},
  {id: 3, name: 'TSLint'}
).pipe(
  groupBy(p => p.id),
  mergeMap((group$) => group$.pipe(reduce((acc, cur) => [...acc, cur], [])))
)
.subscribe(p => console.log(p));
 
// displays:
// [ { id: 1, name: 'JavaScript'},
//   { id: 1, name: 'TypeScript'} ]
//
// [ { id: 2, name: 'Parcel'},
//   { id: 2, name: 'webpack'} ]
//
// [ { id: 3, name: 'TSLint'} ]

groupby angular

content_copyopen_in_new
import { of } from 'rxjs';
import { groupBy, map, mergeMap, reduce } from 'rxjs/operators';
 
of(
  { id: 1, name: 'JavaScript' },
  { id: 2, name: 'Parcel' },
  { id: 2, name: 'webpack' },
  { id: 1, name: 'TypeScript' },
  { id: 3, name: 'TSLint' }
)
  .pipe(
    groupBy(p => p.id, p => p.name),
    mergeMap(group$ =>
      group$.pipe(reduce((acc, cur) => [...acc, cur], [`${group$.key}`]))
    ),
    map(arr => ({ id: parseInt(arr[0], 10), values: arr.slice(1) }))
 )
 .subscribe(p => console.log(p));
 
// displays:
// { id: 1, values: [ 'JavaScript', 'TypeScript' ] }
// { id: 2, values: [ 'Parcel', 'webpack' ] }
// { id: 3, values: [ 'TSLint' ] }