Does this respect the user's locale for number formatting?

Yes, pretty-bytes respects the user's locale for number formatting through the locale option.

The toLocaleString function [index.js:L55-L65] handles locale-aware formatting by calling JavaScript's native Number.toLocaleString() method:

const toLocaleString = (number, locale, options) => {
	let result = number;
	if (typeof locale === 'string' || Array.isArray(locale)) {
		result = number.toLocaleString(locale, options);
	} else if (locale === true || options !== undefined) {
		result = number.toLocaleString(undefined, options);
	}

	return result;
};

The locale option supports three modes [README]:

• false (default): No localization
• true: Uses the system/browser locale
• string or string[]: Uses a specific BCP 47 language tag (e.g., 'de', 'en')

For example, the tests [test.js:L71-L110] demonstrate this:

• German locale: prettyBytes(1001, {locale: 'de'}) → '1 kB' (with German number formatting)
• English locale: prettyBytes(1001, {locale: 'en'}) → '1 kB' (with English number formatting)

This affects not just the number itself but also thousand separators and decimal separators based on locale conventions.

FOLLOW_UPS:

• What formatting options control decimal precision?
• How does the signed option work with locales?
• Can you use both binary and locale options together?