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 Locale identification and negotiation.

options Optional

An object with configuration properties. For numbers, see Number.prototype.toLocaleString(); for dates, see Date.prototype.toLocaleString().

A string representing the elements of the array.

The Array.prototype.toLocaleString method traverses its content, calling the toLocaleString method of every element with the locales and options parameters provided, and concatenates them with a implementation-defined separator (such as a comma ","). Note that the method itself does not consume the two parameters — it only passes them to the toLocaleString() of each element. The choice of the separator string depends on the host's current locale, not the locales parameter.

The elements of the array are converted to strings using their toLocaleString methods.

• Object: Object.prototype.toLocaleString()
• Number: Number.prototype.toLocaleString()
• Date: Date.prototype.toLocaleString()

Always display the currency for the strings and numbers in the prices array:

const prices = ['￥7', 500, 8123, 12];
prices.toLocaleString('ja-JP', { style: 'currency', currency: 'JPY' });

// "￥7,￥500,￥8,123,￥12"

For more examples, see also the Intl.NumberFormat and Intl.DateTimeFormat pages.

• Array.prototype.toString()
• Intl
• Object.prototype.toLocaleString()
• Number.prototype.toLocaleString()
• Date.prototype.toLocaleString()