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Version: 3.35.1

Number.prototype.toLocaleString()

The toLocaleString() method returns a string with a language-sensitive representation of this number. In implementations with Intl.NumberFormat API support, this method simply calls Intl.NumberFormat.

Syntax​

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

Parameters​

The locales and options parameters customize the behavior of the function and let applications specify the language whose formatting conventions should be used.

In implementations that support the Intl.NumberFormat API, these parameters correspond exactly to the Intl.NumberFormat() constructor's parameters. Implementations without Intl.NumberFormat support are asked to ignore both parameters, making the locale used and the form of the string returned entirely implementation-dependent.

  • locales optional

    • : A string with a BCP 47 language tag, or an array of such strings. Corresponds to the locales parameter of the Intl.NumberFormat() constructor.

      In implementations without Intl.NumberFormat support, this parameter is ignored and the host's locale is usually used.

  • options optional

    • : An object adjusting the output format. Corresponds to the options parameter of the Intl.NumberFormat() constructor.

      In implementations without Intl.NumberFormat support, this parameter is ignored.

See the Intl.NumberFormat() constructor for details on these parameters and how to use them.

Return value​

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

In implementations with Intl.NumberFormat, this is equivalent to new Intl.NumberFormat(locales, options).format(number).

Performance​

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