Format currency input in angular 2

Question

I want to format input to USD currency as you type. The input will have 2 decimal places and will enter from right to left. Suppose if I type 54.60 it will be entered as $0.05-->$0.54-->$5.46-->$54.60. This PLUNKER exactly does this, but its in angular js. So far my directive looks like:

import {Directive, Output, EventEmitter} from '@angular/core';
import {NgControl} from '@angular/forms';

@Directive({
  selector: '[formControlName][currency]',
  host: {
    '(ngModelChange)': 'onInputChange($event)',
    '(keydown.backspace)':'onInputChange($event.target.value, true)'
  }
})
export class CurrencyMask {
  constructor(public model: NgControl) {}

  @Output() rawChange:EventEmitter<string> = new EventEmitter<string>();

  onInputChange(event: any, backspace: any) {
    // remove all mask characters (keep only numeric)
    var newVal = event.replace(/\D/g, '');
    var rawValue = newVal;
    var str = (newVal=='0'?'0.0':newVal).split('.');
    str[1] = str[1] || '0';
    newVal= str[0].replace(/(\d)(?=(\d\d\d)+(?!\d))/g, '$1,') + '.' + (str[1].length==1?str[1]+'0':str[1]);



    // set the new value
    this.model.valueAccessor.writeValue(newVal);
    this.rawChange.emit(rawValue)
  }
}

and in html it is being used as:

<input  name="cost" placeholder="cost" class="form-control"  type="text" currency formControlName="cost" (rawChange)="rawCurrency=$event">

Update:

what finally worked for me is:

onInputChange(event: any, backspace: any) {
    var newVal = (parseInt(event.replace(/[^0-9]/g, ''))/100).toLocaleString('en-US', { minimumFractionDigits: 2 });
    var rawValue = newVal;

    if(backspace) {
      newVal = newVal.substring(0, newVal.length - 1);
    }

    if(newVal.length == 0) {
      newVal = '';
    }
    else  {
      newVal = newVal;
    }
    // set the new value
    this.model.valueAccessor.writeValue(newVal);
    this.rawChange.emit(rawValue)
  }

Answer 1

on input change use the following

// remove dot and comma's, 123,456.78 -> 12345678
var strVal = myVal.replace(/\.,/g,'');
// change string to integer
var intVal = parseInt(strVal); 
// divide by 100 to get 0.05 when pressing 5 
var decVal = intVal / 100;
// format value to en-US locale
var newVal = decVal.toLocaleString('en-US', { minimumFractionDigits: 2 });

// or in singel line
var newVal = (parseInt(myVal.replace(/\.,/g, '')) / 100).toLocaleString('en-US', { minimumFractionDigits: 2 });

or

use currency pipe to format to USD format by using only

var newVal = (parseInt(myVal.replace(/\.,/g, '')) / 100)

Hope this helps.

Answer 2

Angular has a formatCurrency method

https://angular.io/api/common/formatCurrency

Here's how I've used it in my code:

demand is a formControl

formatMoney(value: string) {
    this.demand.setValue(
        this.formatMoneyBase(value)
    );
}

formatMoneyBase(value: string = ''): string {
    return value.length ? formatCurrency(parseFloat(value.replace(/\D/g, '')), 'en', '$').replace('$', '') : '';
}