Number and Currency Conversion

Introduction

In the context of internationalization and localization, number and currency conversion is essential for creating applications that can operate in various global markets. This lesson covers the key concepts, formatting techniques, conversion methods, and best practices.

Key Concepts

Number Formatting

Number formatting involves the representation of numbers in a way that aligns with the conventions of a specific locale. This includes:

• Decimal separator (e.g., '.' in the US, ',' in Germany)
• Grouping separator (e.g., ',' in the US, '.' in Germany)
• Currency symbol positioning (e.g., '$100' vs '100€')

Using libraries such as Intl.NumberFormat in JavaScript can help with number formatting:

const number = 1234567.89;
const formattedNumber = new Intl.NumberFormat('de-DE').format(number);
console.log(formattedNumber); // Outputs: "1.234.567,89"

Currency Conversion

Currency conversion is often done using real-time exchange rates, which can be obtained from various financial APIs. Here’s a simple example using a hypothetical API:

async function convertCurrency(amount, fromCurrency, toCurrency) {
    const response = await fetch(`https://api.exchangeratesapi.io/latest?base=${fromCurrency}`);
    const data = await response.json();
    const rate = data.rates[toCurrency];
    return amount * rate;
}

convertCurrency(100, 'USD', 'EUR').then(result => console.log(result)); // Converts 100 USD to EUR

Best Practices

• Use locale-aware libraries for formatting.
• Keep the user informed of the currency they are viewing.
• Update exchange rates regularly if your application involves financial transactions.
• Provide users with the option to select their preferred currency.

FAQ