Convert bytes to a human readable string: 1337 → 1.34 kB. 

Convert bytes to a human readable string: 1337 → 1.34 kB

sindresorhus

pretty-bytes

	Include plus sign for positive numbers. If the difference is exactly zero a space character will be prepended instead for better alignment.

	- If `false`: Output won't be localized.

	- If `true`: Localize the output using the system/browser locale.

	- If `string`: Expects a [BCP 47 language tag](https://en.wikipedia.org/wiki/IETF_language_tag) (For example: `en`, `de`, …)

	- If `string[]`: Expects a list of [BCP 47 language tags](https://en.wikipedia.org/wiki/IETF_language_tag) (For example: `en`, `de`, …)

	readonly locale?: boolean | string | readonly string[];

	Format the number as [bits](https://en.wikipedia.org/wiki/Bit) instead of [bytes](https://en.wikipedia.org/wiki/Byte). This can be useful when, for example, referring to [bit rate](https://en.wikipedia.org/wiki/Bit_rate).

	Format the number using the [Binary Prefix](https://en.wikipedia.org/wiki/Binary_prefix) instead of the [SI Prefix](https://en.wikipedia.org/wiki/SI_prefix). This can be useful for presenting memory amounts. However, this should not be used for presenting file sizes.

	The minimum number of fraction digits to display.

	If neither `minimumFractionDigits` or `maximumFractionDigits` are set, the default behavior is to round to 3 significant digits.

	// Show the number with at least 3 fractional digits

	prettyBytes(1900, {minimumFractionDigits: 3});

	readonly minimumFractionDigits?: number;

	The maximum number of fraction digits to display.

	// Show the number with at most 1 fractional digit

	prettyBytes(1920, {maximumFractionDigits: 1});

	readonly maximumFractionDigits?: number;

	Put a space between the number and unit.

Convert bytes to a human readable string: `1337` → `1.34 kB`.

Formats the given number using `Number#toLocaleString`.

- If locale is a string, the value is expected to be a locale-key (for example: `de`).

- If locale is true, the system default locale is used for translation.

- If no value for locale is specified, the number is returned unmodified.

const toLocaleString = (number, locale, options) => {

	if (typeof locale === 'string' || Array.isArray(locale)) {

		result = number.toLocaleString(locale, options);

	} else if (locale === true || options !== undefined) {

		result = number.toLocaleString(undefined, options);

export default function prettyBytes(number, options) {

		throw new TypeError(`Expected a finite number, got ${typeof number}: ${number}`);

		? (options.binary ? BIBIT_UNITS : BIT_UNITS)

		: (options.binary ? BIBYTE_UNITS : BYTE_UNITS);

	const separator = options.space ? ' ' : '';

	const prefix = isNegative ? '-' : (options.signed ? '+' : '');

	if (options.minimumFractionDigits !== undefined) {

		localeOptions = {minimumFractionDigits: options.minimumFractionDigits};

	if (options.maximumFractionDigits !== undefined) {

		localeOptions = {maximumFractionDigits: options.maximumFractionDigits, ...localeOptions};

		const numberString = toLocaleString(number, options.locale, localeOptions);

		return prefix + numberString + ' ' + UNITS[0];

		return prefix + numberString + separator + UNITS[0];

	const exponent = Math.min(Math.floor(options.binary ? Math.log(number) / Math.log(1024) : Math.log10(number) / 3), UNITS.length - 1);

	number /= (options.binary ? 1024 : 1000) ** exponent;

	const numberString = toLocaleString(Number(number), options.locale, localeOptions);

	return prefix + numberString + ' ' + unit;

	return prefix + numberString + separator + unit;

	"description": "Convert bytes to a human readable string: 1337 → 1.34 kB",

	"repository": "sindresorhus/pretty-bytes",

	"funding": "https://github.com/sponsors/sindresorhus",

> Convert bytes to a human readable string: `1337` → `1.34 kB`

Useful for displaying file sizes for humans.

*Note that it uses base-10 (e.g. kilobyte).

[Read about the difference between kilobyte and kibibyte.](https://web.archive.org/web/20150324153922/https://pacoup.com/2009/05/26/kb-kb-kib-whats-up-with-that/)*