Can I get binary (KiB, MiB) units instead of decimal? How?

Yes, you can get binary units (KiB, MiB, etc.) by using the binary option set to true.

According to the README, here's how:

import prettyBytes from 'pretty-bytes';

prettyBytes(1024, {binary: true});
//=> '1 KiB'

When binary is set to true, the library uses binary prefixes (powers of 1024) instead of SI prefixes (powers of 1000). The available binary units are defined in [index.js:L15-L22] as BIBYTE_UNITS: B, KiB, MiB, GiB, TiB, PiB, EiB, ZiB, YiB.

Note that the README explicitly states: "However, this should not be used for presenting file sizes" — binary prefixes are more appropriate for presenting memory amounts [readme.md:L82-L85].

FOLLOW_UPS:

• How do I format bits with binary prefixes?
• What's the difference between KiB and kB?
• Can I combine binary with the signed option?