A wrapper around Number.prototype.toLocaleString.

The purpose is to provide a unified API for formatting currency amounts regardless of browser support and whether the currency is known or not.

// modern browser
format('da-DK', { currency: 'DKK', major: 1500.5 });
	// 1.500,50 kr.

// legacy browser
format('da-DK', { currency: 'DKK', major: 1500.5 });
	// DKK 1500.50

format({
	locales: [ 'da-DK', 'en-GB' ],
	display: 'code',
	currency: 'GBP',
}, 100.2);
	// 100,20 GBP

format([ opts|locale,] amount|{ currency, major });

Options are:

• currency (three letter ISO)
• locale (e.g. da-DK or simply da)
• locales (an array of prioritized locales, left to right)
• display (one of symbol (default), code or name)
• matcher (best fit (default) or lookup)
• grouping (whether to use thousand separators, detaults to true)
• minimumFractionDigits (used only if localization is not supported, defaults to 2)

$ format-amount --currency USD 124422 --locale en-US
USD 1,244.22