BigInt.prototype.toLocaleString()

The toLocaleString() method returns a string with a language-sensitive representation of this BigInt.

Syntax

bigIntObj.toLocaleString([locales [, options]])

Parameters

The locales and options arguments customize the behavior of the function and let applications specify the language whose formatting conventions should be used. In implementations that ignore the locales and options arguments, the locale used and the form of the string returned are entirely implementation-dependent.

locales Optional

A string with a BCP 47 language tag, or an array of such strings. For the general form and interpretation of the locales argument, see the Intl page. The following Unicode extension key is allowed:

nu
The numbering system to be used. Possible values include: "arab", "arabext", "bali", "beng", "deva", "fullwide", "gujr", "guru", "hanidec", "khmr", "knda", "laoo", "latn", "limb", "mlym", "mong", "mymr", "orya", "tamldec", "telu", "thai", "tibt".
options Optional

An object with some or all of the following properties:

localeMatcher
The locale matching algorithm to use. Possible values are "lookup" and "best fit"; the default is "best fit". For information about this option, see the Intl page.
style
The formatting style to use , the default is "decimal".
  • "decimal" for plain number formatting.
  • "currency" for currency formatting.
  • "percent" for percent formatting
  • "unit   for unit formatting
numberingSystem
Numbering System. Possible values include: "arab", "arabext", " bali", "beng", "deva", "fullwide", " gujr", "guru", "hanidec", "khmr", " knda", "laoo", "latn", "limb", "mlym", " mong", "mymr", "orya", "tamldec", " telu", "thai", "tibt".
unit
The unit to use in unit formatting, Possible values are core unit identifiers, defined in UTS #35, Part 2, Section 6. A subset of units from the full list was selected for use in ECMAScript. Pairs of simple units can be concatenated with "-per-" to make a compound unit. There is no default value; if the style is "unit", the unit property must be provided.
unitDisplay
The unit formatting style to use in unit formatting, the defaults is "short".
  • "long" (e.g., 16 litres)
  • "short" (e.g., 16 l)
  • "narrow" (e.g., 16l)
currency
The currency to use in currency formatting. Possible values are the ISO 4217 currency codes, such as "USD" for the US dollar, "EUR" for the euro, or "CNY" for the Chinese RMB — see the Current currency & funds code list. There is no default value; if the style is "currency", the currency property must be provided.
currencyDisplay
How to display the currency in currency formatting. Possible values are "symbol" to use a localized currency symbol such as €, "code" to use the ISO currency code, "name" to use a localized currency name such as "dollar"; the default is "symbol".
useGrouping
Whether to use grouping separators, such as thousands separators or thousand/lakh/crore separators. Possible values are true and false; the default is true.

The following properties fall into two groups: minimumIntegerDigits, minimumFractionDigits, and maximumFractionDigits in one group, minimumSignificantDigits and maximumSignificantDigits in the other. If at least one property from the second group is defined, then the first group is ignored.

minimumIntegerDigits
The minimum number of integer digits to use. Possible values are from 1 to 21; the default is 1.
minimumFractionDigits
The minimum number of fraction digits to use. Possible values are from 0 to 20; the default for plain number and percent formatting is 0; the default for currency formatting is the number of minor unit digits provided by the ISO 4217 currency code list (2 if the list doesn't provide that information).
maximumFractionDigits
The maximum number of fraction digits to use. Possible values are from 0 to 20; the default for plain number formatting is the larger of minimumFractionDigits and 3; the default for currency formatting is the larger of minimumFractionDigits and the number of minor unit digits provided by the ISO 4217 currency code list (2 if the list doesn't provide that information); the default for percent formatting is the larger of minimumFractionDigits and 0.
minimumSignificantDigits
The minimum number of significant digits to use. Possible values are from 1 to 21; the default is 1.
maximumSignificantDigits
The maximum number of significant digits to use. Possible values are from 1 to 21; the default is 21.
notation
The formatting that should be displayed for the number, the defaults is "standard"
  • "standard"  plain number formatting 
  • "scientific"  return the order-of-magnitude for formatted number.
  • "engineering"  return the exponent of ten when divisible by three 
  • "compact" string representing exponent, defaults is using the "short" form  
    • "compactDisplay" used only when notation is "compact", takes either "short" (default) or "long"

Return value

A string with a language-sensitive representation of the given BigInt.

Examples

Using toLocaleString

In basic use without specifying a locale, a formatted string in the default locale and with default options is returned.

var bigint = 3500n;

bigint.toLocaleString();
// Displays "3,500" if in U.S. English locale

Using locales

This example shows some of the variations in localized number formats. In order to get the format of the language used in the user interface of your application, make sure to specify that language (and possibly some fallback languages) using the locales argument:

var bigint = 123456789123456789n;

// German uses period for thousands
console.log(bigint.toLocaleString('de-DE'));
// → 123.456.789.123.456.789

// Arabic in most Arabic speaking countries uses Eastern Arabic digits
console.log(bigint.toLocaleString('ar-EG'));
// → ١٢٣٬٤٥٦٬٧٨٩٬١٢٣٬٤٥٦٬٧٨٩

// India uses thousands/lakh/crore separators
console.log(bigint.toLocaleString('en-IN'));
// → 1,23,45,67,89,12,34,56,789

// the nu extension key requests a numbering system, e.g. Chinese decimal
console.log(bigint.toLocaleString('zh-Hans-CN-u-nu-hanidec'));
// → 一二三,四五六,七八九,一二三,四五六,七八九

// when requesting a language that may not be supported, such as
// Balinese, include a fallback language, in this case Indonesian
console.log(bigint.toLocaleString(['ban', 'id']));
// → 123.456.789.123.456.789

Using options

The results provided by toLocaleString can be customized using the options argument:

var bigint = 123456789123456789n;

// request a currency format
console.log(bigint.toLocaleString('de-DE', { style: 'currency', currency: 'EUR' }));
// → 123.456.789.123.456.789,00 €

// the Japanese yen doesn't use a minor unit
console.log(bigint.toLocaleString('ja-JP', { style: 'currency', currency: 'JPY' }))
// → ¥123,456,789,123,456,789

// limit to three significant digits
console.log(bigint.toLocaleString('en-IN', { maximumSignificantDigits: 3 }));
// → 1,23,00,00,00,00,00,00,000

Performance

When formatting large numbers of numbers, it is better to create a NumberFormat object and use the function provided by its NumberFormat.format property.

Specifications

Specification
BigInt

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
toLocaleStringChrome Full support 67Edge No support NoFirefox Full support 68IE No support NoOpera Full support 54Safari No support NoWebView Android Full support 67Chrome Android Full support 67Firefox Android Full support 68Opera Android Full support 48Safari iOS No support NoSamsung Internet Android Full support 9.0nodejs Full support 10.4.0
localesChrome Full support 76Edge No support NoFirefox Full support 70IE No support NoOpera No support NoSafari No support NoWebView Android Full support 76Chrome Android Full support 76Firefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android No support Nonodejs No support No
optionsChrome Full support 76Edge No support NoFirefox Full support 70IE No support NoOpera No support NoSafari No support NoWebView Android Full support 76Chrome Android Full support 76Firefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android No support Nonodejs No support No

Legend

Full support  
Full support
No support  
No support

See also