Is it correct to implement a custom NgbDateParserFormatter to change the format of the input value on NgbInputDatepicker?
As of today implementing a custom NgbDateParserFormatter is the best way to go. So yes, it is a correct way.
In the future we might have a more sophisticated implementation of the NgbDateParserFormatter where you will be able to just pass a desired format (ex. yyyy-MM-dd). Adding this feature will depend on user's interest.
You might also check some more background info in https://github.com/ng-bootstrap/ng-bootstrap/issues/754#issuecomment-247767027
Create custom parser formatter.
import { NgbDateParserFormatter, NgbDateStruct } from '@ng-bootstrap/ng-bootstrap';import { Injectable } from '@angular/core';@Injectable()export class NgbDateCustomParserFormatter extends NgbDateParserFormatter { format(date: NgbDateStruct): string { return date ? `${isNumber(date.day) ? padNumber(date.day) : ''}-${isNumber(date.month) ? padNumber(date.month) : ''}-${date.year}` : ''; }}Set the provider for the custom parser formatter in the @NgModule.
providers: [ {provide: NgbDateParserFormatter, useClass: NgbDateCustomParserFormatter}]As described in the api