BigInt.prototype.toLocaleString()

Baseline Widely available

This feature is well established and works across many devices and browser versions. Its been available across browsers since 2020 9.

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BigInt toLocaleString() BigInt . Intl.NumberFormat API Intl.NumberFormat .

toLocaleString . NumberFormat format() . format Intl.NumberFormat format() .

const bigint = 123456789123456789n;

// German uses period for thousands
console.log(bigint.toLocaleString("de-DE"));
// Expected output: "123.456.789.123.456.789"

// Request a currency format
console.log(
  bigint.toLocaleString("de-DE", { style: "currency", currency: "EUR" }),
);
// Expected output: "123.456.789.123.456.789,00 "

toLocaleString()
toLocaleString(locales)
toLocaleString(locales, options)

locales and options .

Intl.NumberFormat API Intl.NumberFormat() . Intl.NumberFormat .

locales Optional

BCP 47 . Intl.NumberFormat() locales .

Intl.NumberFormat .

options Optional

. Intl.NumberFormat() options .

Intl.NumberFormat .

Intl.NumberFormat() .

BigInt .

Intl.NumberFormat new Intl.NumberFormat(locales, options).format(number) .

: toLocaleString() . , , . toLocaleString() .

toLocaleString()

locale .

const bigint = 3500n;

console.log(bigint.toLocaleString());
// "3,500" U.S English

locales options

locales locales API . toLocaleString() . locales options Intl , .

function toLocaleStringSupportsLocales() {
  return (
    typeof Intl === "object" &&
    !!Intl &&
    typeof Intl.NumberFormat === "function"
  );
}

locales

. locales ( ) .

const bigint = 123456789123456789n;

//     .
console.log(bigint.toLocaleString("de-DE"));
// 123.456.789.123.456.789

//       .
console.log(bigint.toLocaleString("ar-EG"));
// 

//   /lakh/crore   .
console.log(bigint.toLocaleString("en-IN"));
// 1,23,45,67,89,12,34,56,789

// nu     .(:  10)
console.log(bigint.toLocaleString("zh-Hans-CN-u-nu-hanidec"));
// ,,,,,

//           (  ) .
console.log(bigint.toLocaleString(["ban", "id"]));
// 123.456.789.123.456.789

options

toLocaleString() options .

const bigint = 123456789123456789n;

//   
console.log(
  bigint.toLocaleString("de-DE", { style: "currency", currency: "EUR" }),
);
// 123.456.789.123.456.789,00 

//     
console.log(
  bigint.toLocaleString("ja-JP", { style: "currency", currency: "JPY" }),
);
// 123,456,789,123,456,789

//  3 
console.log(bigint.toLocaleString("en-IN", { maximumSignificantDigits: 3 }));
// 1,23,00,00,00,00,00,00,000

Specification
ECMAScript 2027 Internationalization API Specification # sup-bigint.prototype.tolocalestring

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