Custom DateFormats & DateAdapter for Angular Material MatDatepicker using Day.js

date-formats.ts

import { Platform } from '@angular/cdk/platform';
import { NativeDateAdapter } from '@angular/material';
import * as dayjs from 'dayjs';
import 'dayjs/locale/de';
import * as customParseFormat from 'dayjs/plugin/customParseFormat';
import * as localizedFormat from 'dayjs/plugin/localizedFormat';


/**
* Custom Date-Formats and Adapter (using https://github.com/iamkun/dayjs)
*/

export const AppDateFormats = {
  parse: {
    dateInput: 'DD.MM.YYYY',
  },
  display: {
    dateInput: 'DD.MM.YYYY',
    monthYearLabel: 'MMM YYYY',
    dateA11yLabel: 'LL',
    monthYearA11yLabel: 'MMMM YYYY',
  }
}

export class AppDateAdapter extends NativeDateAdapter {

  constructor(matDateLocale: string, platform: Platform) {
    super(matDateLocale, platform)

    // Initalize DayJS-Parser
    dayjs.locale('de')
    dayjs.extend(customParseFormat)
    dayjs.extend(localizedFormat)
  }

  parse(value: any): Date | null {
    return dayjs(value, 'DD.MM.YYYY').toDate()
  }

  format(date: Date, displayFormat: any): string {
    return dayjs(date).format(displayFormat)
  }

}

shared.module.ts

/* ... */

/* Adding Providers in a Shared- or App-Module */


@NgModule({

  providers: [
    {
      provide: DateAdapter,
      useClass: AppDateAdapter,
      deps: [MAT_DATE_LOCALE, Platform]
    },
    {
      provide: MAT_DATE_FORMATS,
      useValue: AppDateFormats
    }
  ]

})
export class SharedModule { }

had you made a new class 'AppDateAdapter' here?

Not really, just override the the format function. But couldn't find any example on the web and yours helped me. I wanted to share my variant just in case someone would need it. (I decided to keep most of my dates with the default javascript object for now. I don't have enough situations were a date library would be needed)