{toCurrency(amount, { localeCode: locale })}
);
}
```
### Node.js / Express
```ts
import express from 'express';
import { toWords, toCurrency, detectLocale } from 'to-words';
const app = express();
app.get('/convert', (req, res) => {
const number = String(req.query.number ?? '');
const locale = String(req.query.locale ?? detectLocale());
const currency = req.query.currency === 'true';
try {
const result = currency ? toCurrency(number, { localeCode: locale }) : toWords(number, { localeCode: locale });
res.json({ result, locale });
} catch (e) {
res.status(400).json({ error: (e as Error).message });
}
});
```
## 🌍 Numbering Systems
Different regions use different numbering systems. This library supports all major systems:
### Short Scale (Western)
Used in: USA, UK, Canada, Australia, and most English-speaking countries.
| Number | Name |
| ------ | ------------ |
| 10^6 | Million |
| 10^9 | Billion |
| 10^12 | Trillion |
| 10^15 | Quadrillion |
| ... | ... |
| 10^63 | Vigintillion |
```js
const toWords = new ToWords({ localeCode: 'en-US' });
toWords.convert(1000000000000000000n);
// "One Quintillion"
```
### Long Scale (European)
Used in: Germany, France, and many European countries.
| Number | German | French |
| ------ | --------- | -------- |
| 10^6 | Million | Million |
| 10^9 | Milliarde | Milliard |
| 10^12 | Billion | Billion |
| 10^15 | Billiarde | Billiard |
```js
const toWords = new ToWords({ localeCode: 'de-DE' });
toWords.convert(1000000000);
// "Eins Milliarde"
```
### Indian System
Used in: India, Bangladesh, Nepal, Pakistan.
| Number | Name |
| ------ | ------ |
| 10^5 | Lakh |
| 10^7 | Crore |
| 10^9 | Arab |
| 10^11 | Kharab |
| 10^13 | Neel |
| 10^15 | Padma |
| 10^17 | Shankh |
```js
const toWords = new ToWords({ localeCode: 'en-IN' });
toWords.convert(100000000000000000n);
// "One Shankh"
const toWordsHindi = new ToWords({ localeCode: 'hi-IN' });
toWordsHindi.convert(100000000000000000n);
// "एक शंख"
```
### East Asian System
Used in: Japan, China, Korea.
| Number | Character |
| ------ | ------------- |
| 10^4 | 万 (Man/Wan) |
| 10^8 | 億 (Oku/Yi) |
| 10^12 | 兆 (Chō/Zhao) |
| 10^16 | 京 (Kei/Jing) |
| 10^20 | 垓 (Gai) |
```js
const toWords = new ToWords({ localeCode: 'ja-JP' });
toWords.convert(100000000);
// "一 億"
```
## ⚙️ API Reference
### Constructor Options
```typescript
interface ToWordsOptions {
localeCode?: string; // Default: 'en-IN'
converterOptions?: {
currency?: boolean; // Default: false
ignoreDecimal?: boolean; // Default: false
ignoreZeroCurrency?: boolean; // Default: false
doNotAddOnly?: boolean; // Default: false
includeZeroFractional?: boolean; // Default: false
currencyOptions?: {
name: string;
plural: string;
symbol: string;
fractionalUnit: {
name: string;
plural: string;
symbol: string;
};
};
};
}
```
### Class Methods
#### `convert(number, options?)`
Converts a number to words.
- **number**: `number | bigint | string` — The number to convert
- **options**: `ConverterOptions` — Override instance options
- **returns**: `string` — The number in words
#### `toOrdinal(number, options?)`
Converts a number to ordinal words.
- **number**: `number | bigint | string` — The number to convert (must be a non-negative integer value)
- **options**: `OrdinalOptions` — Optional settings (`{ formal?: boolean }`)
- **returns**: `string` — The ordinal in words (e.g., "First", "Twenty Third")
### Functional Exports
The three conversion helpers (`toWords`, `toOrdinal`, `toCurrency`) are available from the full bundle (`to-words`) and from every per-locale entry point (`to-words/