Q499: What is the Intl.NumberFormat API and how is it used? - JavaScript Internals (521 Qs)

The Intl.NumberFormat API provides language-sensitive number formatting, allowing you to format numbers according to locale-specific conventions.

javascript

 // Basic usage
 const formatter = new Intl.NumberFormat('en-US');
 console.log(formatter.format(1234567.89)); // "1,234,567.89"

 // Different locales
 console.log(new Intl.NumberFormat('de-DE').format(1234567.89));
 // "1.234.567,89"

 console.log(new Intl.NumberFormat('hi-IN').format(1234567.89));
 // "12,34,567.89"

Currency formatting:

javascript

 const usdFormatter = new Intl.NumberFormat('en-US', {
   style: 'currency',
   currency: 'USD'
 });
 console.log(usdFormatter.format(1234.56)); // "$1,234.56"

 const euroFormatter = new Intl.NumberFormat('de-DE', {
   style: 'currency',
   currency: 'EUR'
 });
 console.log(euroFormatter.format(1234.56)); // "1.234,56 €"

Percentage formatting:

javascript

 const percentFormatter = new Intl.NumberFormat('en-US', {
   style: 'percent',
   minimumFractionDigits: 2
 });
 console.log(percentFormatter.format(0.1234)); // "12.34%"

Unit formatting:

javascript

 const distanceFormatter = new Intl.NumberFormat('en-US', {
   style: 'unit',
   unit: 'kilometer',
   unitDisplay: 'long'
 });
 console.log(distanceFormatter.format(50)); // "50 kilometers"

Advanced options:

javascript

 const formatter = new Intl.NumberFormat('en-US', {
   minimumFractionDigits: 2,
   maximumFractionDigits: 2,
   useGrouping: true
 });
 console.log(formatter.format(1234.5)); // "1,234.50"