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 locale option supports multiple modes [index.js:L55-L65]:

• false (default): Output won't be localized—numbers use standard formatting
• true: Uses the system/browser locale automatically
• string: Accepts a BCP 47 language tag (e.g., 'de', 'en')
• string[]: Accepts a list of language tags with fallback support

The implementation uses the toLocaleString function [index.js:L55-L65], which calls Number#toLocaleString() with the specified locale. For example:

• prettyBytes(1337, {locale: 'de'}) → '1,34 kB' (German decimal separator)
• prettyBytes(1337, {locale: 'en'}) → '1.34 kB' (English decimal separator)
• prettyBytes(1e30, {locale: 'en'}) → '1,000,000 YB' (English thousand separators)
• prettyBytes(1e30, {locale: 'de'}) → '1.000.000 YB' (German thousand separators)

The test file [test.js:L71-L110] confirms these locale-aware behaviors across different scenarios including negative numbers and very large values.

FOLLOW_UPS:

• What other formatting options does pretty-bytes support?
• How does the binary prefix option work?
• Can you customize decimal places in output?