runtut_currency_input_formatter

A lightweight Flutter package for formatting currency input fields.

Pass a locale and an ISO 4217 currency code — separators and decimal digits are derived automatically.

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Why

Most currency formatters either hardcode a locale or make you configure separators by hand. This one takes a locale and a currency code and figures out the rest: id_ID + IDR gives you . thousands and , decimal with no decimal places; en_US + USD gives you , thousands and . decimal with 2 places.

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Usage

import 'package:runtut_currency_input_formatter/runtut_currency_input_formatter.dart';

TextField(
  inputFormatters: [
    CurrencyInputFormatter(locale: 'id_ID', currencyCode: 'IDR'),
  ],
)

IDR — 1.000.000

CurrencyInputFormatter() // defaults to locale: 'id_ID', currencyCode: 'IDR'

USD — 1,000,000.99

CurrencyInputFormatter(locale: 'en_US', currencyCode: 'USD')

EUR — 1.000.000,99

CurrencyInputFormatter(locale: 'de_DE', currencyCode: 'EUR')

JPY — 1,000,000

CurrencyInputFormatter(locale: 'ja_JP', currencyCode: 'JPY')

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Options

Parameter	Type	Default	Description
locale	String	'id_ID'	Locale code — determines thousand and decimal separators
currencyCode	String	'IDR'	ISO 4217 currency code — determines decimal digit count

Currencies with 0 decimal places (e.g. IDR, JPY, KRW, VND) reject decimal input entirely. All others use 2 decimal places.

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Notes

• Cursor position is preserved correctly across formatting changes
• Thousand separators injected by the formatter are transparent to backspace — deleting one consumes the digit to its left instead

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Built with care. Extracted from Runtut — a financial journal for everyday spending.