Intl.NumberFormat

const number = 3500;

console.log(new Intl.NumberFormat().format(number));
// '3,500' if in US English locale

const number = 123456.789;

// German uses comma as decimal separator and period for thousands
console.log(new Intl.NumberFormat("de-DE").format(number));
// 123.456,789

// Arabic in most Arabic speaking countries uses real Arabic digits
console.log(new Intl.NumberFormat("ar-EG").format(number));
// ١٢٣٤٥٦٫٧٨٩

// India uses thousands/lakh/crore separators
console.log(new Intl.NumberFormat("en-IN").format(number));
// 1,23,456.789

// the nu extension key requests a numbering system, e.g. Chinese decimal
console.log(new Intl.NumberFormat("zh-Hans-CN-u-nu-hanidec").format(number));
// 一二三,四五六.七八九

// when requesting a language that may not be supported, such as
// Balinese, include a fallback language, in this case Indonesian
console.log(new Intl.NumberFormat(["ban", "id"]).format(number));
// 123.456,789

const number = 123456.789;

// request a currency format
console.log(
  new Intl.NumberFormat("de-DE", { style: "currency", currency: "EUR" }).format(
    number,
  ),
);
// 123.456,79 €

// the Japanese yen doesn't use a minor unit
console.log(
  new Intl.NumberFormat("ja-JP", { style: "currency", currency: "JPY" }).format(
    number,
  ),
);
// ￥123,457

// limit to three significant digits
console.log(
  new Intl.NumberFormat("en-IN", { maximumSignificantDigits: 3 }).format(
    number,
  ),
);
// 1,23,000

// Formatting with units
console.log(
  new Intl.NumberFormat("pt-PT", {
    style: "unit",
    unit: "kilometer-per-hour",
  }).format(50),
);
// 50 km/h

console.log(
  (16).toLocaleString("en-GB", {
    style: "unit",
    unit: "liter",
    unitDisplay: "long",
  }),
);
// 16 litres