Victor date picker

gistfile1.ts

import { Component } from '@angular/core';
import { NgbDateStruct, NgbDateParserFormatter } from '@ng-bootstrap/ng-bootstrap';

const now = new Date();

function toInteger(value: any): number {
  return parseInt(`${value}`, 10);
}

function isNumber(value: any): value is number {
  return !isNaN(toInteger(value));
}

function padNumber(value: number) {
  if (isNumber(value)) {
    return `0${value}`.slice(-2);
  } else {
    return '';
  }
}

export class NgbDateVictorParserFormatter extends NgbDateParserFormatter {
  parse(value: string): NgbDateStruct {
    if (value) {
      const dateParts = value.trim().split('/');
      if (dateParts.length === 1 && isNumber(dateParts[0])) {
        return {year: toInteger(dateParts[0]), month: null, day: null};
      } else if (dateParts.length === 2 && isNumber(dateParts[0]) && isNumber(dateParts[1])) {
        return {year: toInteger(dateParts[0]), month: toInteger(dateParts[1]), day: null};
      } else if (dateParts.length === 3 && isNumber(dateParts[0]) && isNumber(dateParts[1]) && isNumber(dateParts[2])) {
        return {year: toInteger(dateParts[0]), month: toInteger(dateParts[1]), day: toInteger(dateParts[2])};
      }
    }
    return null;
  }

  format(date: NgbDateStruct): string {
    return date ?
        `${isNumber(date.day) ? padNumber(date.day) : ''}/${isNumber(date.month) ? padNumber(date.month) : ''}/${date.year}` :
        '';
  }
}

@Component({
  selector: 'my-app',
  providers: [{provide: NgbDateParserFormatter, useClass: NgbDateVictorParserFormatter}],
  template: `
    <form class="form-inline">
      <div class="form-group">
        <div class="input-group">
          <input class="form-control" 
                 placeholder="yyyy-mm-dd"
                 name="dp"
                [(ngModel)]="model"
                ngbDatepicker 
                #d="ngbDatepicker">

          <button class="input-group-addon" (click)="d.toggle()" type="button">
            x
          </button>

        </div>
      </div>
    </form>

    <hr/>
    <pre>Model: {{ model | json }}</pre> 
  `
})
export class AppComponent  {
  model: NgbDateStruct;
  date: {year: number, month: number};

  selectToday() {
    this.model = {year: now.getFullYear(), month: now.getMonth() + 1, day: now.getDate()};
  }
}