numberpicker

import { FormControl } from '@angular/forms';
import { Component, EventEmitter, OnInit, Input, Output } from '@angular/core';

/*
  Generated class for the NumberPicker component.

  See https://angular.io/docs/ts/latest/api/core/index/ComponentMetadata-class.html
  for more info on Angular 2 Components.
*/
@Component({
  selector: 'number-picker',
  templateUrl: 'number-picker.html'
})
export class NumberPickerComponent implements OnInit {
  @Input() min: number;
  @Input() max: number;
  @Input() step: number;
  @Input() precision: number;
  @Input() inputDisabled: boolean;
  @Output() onChange: EventEmitter<number> = new EventEmitter();

  private numberPicker: FormControl;

  constructor() { }

  ngOnInit() {
    if (this.inputDisabled == null) {
      this.inputDisabled = false;
    }
    if (this.min == null) {
      this.min = 0;
    }
    if (this.max == null) {
      this.max = 100;
    }
    if (this.precision == null) {
      this.precision = 1;
    }
    if (this.step == null) {
      this.step = 1;
    }

    this.numberPicker = new FormControl({ value: this.min, disabled: this.inputDisabled });
    this.numberPicker.registerOnChange(() => {
      this.onChange.emit(this.numberPicker.value);
    });
  }

  private increaseValue(): void {
    var currentValue = this.numberPicker.value;
    if (currentValue < this.max) {
      currentValue = currentValue + this.step;
      if (this.precision != null) {
        currentValue = this.round(currentValue, this.precision);
      }
      this.numberPicker.setValue(currentValue);
    }
  }

  private decreaseValue(): void {
    var currentValue = this.numberPicker.value;
    if (currentValue > this.min) {
      currentValue = currentValue - this.step;
      if (this.precision != null) {
        currentValue = this.round(currentValue, this.precision);
      }
      this.numberPicker.setValue(currentValue);
    }
  }

  private round(value: number, precision: number): number {
    let multiplier: number = Math.pow(10, precision || 0);
    return Math.round(value * multiplier) / multiplier;
  }

  public getValue(): number {
    return this.numberPicker.value;
  }

}