Control number of fraction digits through localeOptions option.

index.d.ts

@@ -19,6 +19,25 @@ declare namespace prettyBytes {
 		*/
 		readonly locale?: boolean | string | readonly string[];
 
+		/**
+		[NumberFormat](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat) international localization options.
+
+		The options `minimumFractionDigits` and `maximumFractionDigits` can be used to control the number of fractional digits displayed.
+
+		@default undefined
+
+		```
+		import prettyBytes = require('pretty-bytes');
+
+		prettyBytes(1900, {localeOptions: {maximumFractionDigits: 1}});
+		//=> '1.9 kB'
+
+		prettyBytes(1900, {localeOptions: {minimumFractionDigits: 3}});
+		//=> '1.900 kB'
+		```
+		*/
+		readonly localeOptions?: object;
+
 		/**
 		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).
 
@@ -51,23 +70,6 @@ declare namespace prettyBytes {
 		```
 		*/
 		readonly binary?: boolean;
-
-		/**
-		Number of fraction digits to show when displaying bytes or bits.
-
-		@default undefined
-
-		```
-		import prettyBytes = require('pretty-bytes');
-
-		prettyBytes(1911);
-		// => '1.91 kB'
-
-		prettyBytes(1911, {digits: 1});
-		//=> '1.9 kB'
-		```
-		*/
-		readonly digits?: number;
 	}
 }
 

index.js

@@ -87,26 +87,22 @@ module.exports = (number, options) => {
 		number = -number;
 	}
 
-	const locale = options.digits && !options.locale ? true : options.locale;
-	const localeOptions = options.digits ? {
-		minimumFactionDigits: options.digits,
-		maximumFractionDigits: options.digits
-	} : undefined;
+	const locale = !options.locale && options.localeOptions ? true : options.locale;
 
 	if (number < 1) {
-		const numberString = toLocaleString(number, locale, localeOptions);
+		const numberString = toLocaleString(number, locale, options.localeOptions);
 		return prefix + numberString + ' ' + UNITS[0];
 	}
 
 	const exponent = Math.min(Math.floor(options.binary ? Math.log(number) / Math.log(1024) : Math.log10(number) / 3), UNITS.length - 1);
 	// eslint-disable-next-line unicorn/prefer-exponentiation-operator
 	number /= Math.pow(options.binary ? 1024 : 1000, exponent);
 
-	if (!options.digits) {
+	if (!options.localeOptions) {
 		number = number.toPrecision(3);
 	}
 
-	const numberString = toLocaleString(Number(number), locale, localeOptions);
+	const numberString = toLocaleString(Number(number), locale, options.localeOptions);
 
 	const unit = UNITS[exponent];
 

readme.md

@@ -72,13 +72,6 @@ Default: `false`
 
 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.
 
-##### digits
-
-Type: `number`\
-Default: `undefined`
-
-Number of fraction digits to show when displaying bytes or bits. If locale is not set, the number will be automatically localized using the system default localization.
-
 ##### locale
 
 Type: `boolean | string`\
@@ -92,6 +85,25 @@ Default: `false` *(No localization)*
 
 **Note:** Localization should generally work in browsers. Node.js needs to be [built](https://github.com/nodejs/node/wiki/Intl) with `full-icu` or `system-icu`. Alternatively, the [`full-icu`](https://github.com/unicode-org/full-icu-npm) module can be used to provide support at runtime. [Node.js 13](https://nodejs.org/en/blog/release/v13.0.0/) and later ships with ICU by default.
 
+##### localeOptions
+
+Type: `object`\
+Default: `undefined`
+
+[NumberFormat](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat) international localization options. The options `minimumFractionDigits` and `maximumFractionDigits` can be used to control the number of fractional digits displayed.
+
+```js
+const prettyBytes = require('pretty-bytes');
+
+// Show number with at most 1 fractional digit
+prettyBytes(1900, {localeOptions: {maximumFractionDigits: 1}});
+//=> '1.9 kB'
+
+// Show number with at least 3 fractional digits
+prettyBytes(1900, {localeOptions: {minimumFractionDigits: 3}});
+//=> '1.900 kB'
+```
+
 ## Related
 
 - [pretty-bytes-cli](https://github.com/sindresorhus/pretty-bytes-cli) - CLI for this module

test.js

@@ -74,6 +74,18 @@ test('locale option', t => {
 	}
 });
 
+test('localeOptions option', t => {
+	t.is(prettyBytes(1900, {localeOptions: {maximumFractionDigits: 1}}), '1.9 kB');
+	t.is(prettyBytes(1900, {localeOptions: {minimumFractionDigits: 3}}), '1.900 kB');
+	t.is(prettyBytes(1911, {localeOptions: {maximumFractionDigits: 1}}), '1.9 kB');
+	t.is(prettyBytes(1111, {localeOptions: {maximumFractionDigits: 2}}), '1.11 kB');
+	t.is(prettyBytes(1019, {localeOptions: {maximumFractionDigits: 3}}), '1.019 kB');
+	t.is(prettyBytes(1001, {localeOptions: {maximumFractionDigits: 3}}), '1.001 kB');
+	t.is(prettyBytes(4001, {localeOptions: {maximumFractionDigits: 3}, binary: true}), '3.907 kB');
+	t.is(prettyBytes(18717, {localeOptions: {maximumFractionDigits: 2}, binary: true}), '18.28 kB');
+	t.is(prettyBytes(18717, {localeOptions: {maximumFractionDigits: 4}, binary: true}), '18.2783 kB');
+});
+
 test('signed option', t => {
 	t.is(prettyBytes(42, {signed: true}), '+42 B');
 	t.is(prettyBytes(-13, {signed: true}), '-13 B');
@@ -113,17 +125,3 @@ test('bits and binary option', t => {
 	t.is(prettyBytes(1025, {bits: true, binary: true}), '1 kibit');
 	t.is(prettyBytes(1e6, {bits: true, binary: true}), '977 kibit');
 });
-
-test('digits option', t => {
-	t.is(prettyBytes(1001), '1 kB');
-	t.is(prettyBytes(1111), '1.11 kB');
-	t.is(prettyBytes(1911), '1.91 kB');
-	t.is(prettyBytes(1900, {digits: 1}), '1.9 kB');
-	t.is(prettyBytes(1911, {digits: 1}), '1.9 kB');
-	t.is(prettyBytes(1111, {digits: 2}), '1.11 kB');
-	t.is(prettyBytes(1019, {digits: 3}), '1.019 kB');
-	t.is(prettyBytes(1001, {digits: 3}), '1.001 kB');
-	t.is(prettyBytes(4001, {digits: 3, binary: true}), '3.907 kB');
-	t.is(prettyBytes(18717, {digits: 2, binary: true}), '18.28 kB');
-	t.is(prettyBytes(18717, {digits: 4, binary: true}), '18.2783 kB');
-});