How to Format Numbers as Currency Strings

Formatting numbers as currency strings is a common requirement in JavaScript applications. Whether you are building an e-commerce website or a financial application, it is important to present numbers in a clear and consistent format. In this blog post, we will explore different ways to format numbers as currency strings using JavaScript.

Solution 1: Using the toLocaleString() Method
The toLocaleString() method is a built-in JavaScript method that can be used to format numbers according to the locale of the user. By passing the “en-US” option to this method, we can format numbers as currency strings in the US format.

const number = 123456.789;
const currencyString = number.toLocaleString("en-US", { style: "currency", currency: "USD" });

console.log(currencyString); // $123,456.79

Solution 2: Using the Intl.NumberFormat() Constructor
The Intl.NumberFormat() constructor is another built-in JavaScript feature that provides more control over number formatting. We can create an instance of this constructor and specify the desired options to format numbers as currency strings.

const number = 123456.789;
const formatter = new Intl.NumberFormat("en-US", { style: "currency", currency: "USD" });
const currencyString = formatter.format(number);

console.log(currencyString); // $123,456.79

Solution 3: Using a Custom Function
If you prefer a more customized approach, you can create a custom function to format numbers as currency strings. This function can handle different locales and currency symbols based on your specific requirements.

function formatCurrency(number, locale, currency) {
  const formatter = new Intl.NumberFormat(locale, { style: "currency", currency });
  return formatter.format(number);
}

const number = 123456.789;
const currencyString = formatCurrency(number, "en-US", "USD");

console.log(currencyString); // $123,456.79

In conclusion, formatting numbers as currency strings in JavaScript can be easily achieved using the toLocaleString() method, the Intl.NumberFormat() constructor, or a custom function. Choose the method that best suits your needs and provides the desired formatting options.