Add bits option (#53)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

index.d.ts

@@ -17,6 +17,20 @@ declare namespace prettyBytes {
 		@default false
 		*/
 		readonly locale?: boolean | 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).
+		
+		@default false
+		
+		```
+		import prettyBytes = require('pretty-bytes');
+
+		prettyBytes(1337, {bits: true});
+		//=> '1.34 kbit'
+		```
+		*/
+		readonly bits?: boolean;
 	}
 }
 

index.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const UNITS = [
+const BYTE_UNITS = [
 	'B',
 	'kB',
 	'MB',
@@ -12,6 +12,18 @@ const UNITS = [
 	'YB'
 ];
 
+const BIT_UNITS = [
+	'b',
+	'kbit',
+	'Mbit',
+	'Gbit',
+	'Tbit',
+	'Pbit',
+	'Ebit',
+	'Zbit',
+	'Ybit'
+];
+
 /*
 Formats the given number using `Number#toLocaleString`.
 - If locale is a string, the value is expected to be a locale-key (for example: `de`).
@@ -34,10 +46,11 @@ module.exports = (number, options) => {
 		throw new TypeError(`Expected a finite number, got ${typeof number}: ${number}`);
 	}
 
-	options = Object.assign({}, options);
+	options = Object.assign({bits: false}, options);
+	const UNITS = options.bits ? BIT_UNITS : BYTE_UNITS;
 
 	if (options.signed && number === 0) {
-		return ' 0 B';
+		return ' 0 ' + UNITS[0];
 	}
 
 	const isNegative = number < 0;
@@ -49,7 +62,7 @@ module.exports = (number, options) => {
 
 	if (number < 1) {
 		const numberString = toLocaleString(number, options.locale);
-		return prefix + numberString + ' B';
+		return prefix + numberString + ' ' + UNITS[0];
 	}
 
 	const exponent = Math.min(Math.floor(Math.log10(number) / 3), UNITS.length - 1);

index.test-d.ts

@@ -7,3 +7,4 @@ expectType<string>(prettyBytes(1337));
 expectType<string>(prettyBytes(42, {signed: true}));
 expectType<string>(prettyBytes(1337, {locale: 'de'}));
 expectType<string>(prettyBytes(1337, {locale: true}));
+expectType<string>(prettyBytes(1337, {bits: true}));

readme.md

@@ -26,6 +26,10 @@ prettyBytes(1337);
 prettyBytes(100);
 //=> '100 B'
 
+// Display with units of bits
+prettyBytes(1337, {bits: true});
+//=> '1.34 kbit'
+
 // Display file size differences
 prettyBytes(42, {signed: true});
 //=> '+42 B'
@@ -57,6 +61,12 @@ Default: `false`
 
 Include plus sign for positive numbers. If the difference is exactly zero a space character will be prepended instead for better alignment.
 
+##### bits
+
+Type: `boolean`<br>
+Default: `false`
+
+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).
 
 ##### locale
 

test.js

@@ -69,3 +69,16 @@ test('signed option', t => {
 	t.is(prettyBytes(-13, {signed: true}), '-13 B');
 	t.is(prettyBytes(0, {signed: true}), ' 0 B');
 });
+
+test('bits option', t => {
+	t.is(prettyBytes(0, {bits: true}), '0 b');
+	t.is(prettyBytes(0.4, {bits: true}), '0.4 b');
+	t.is(prettyBytes(0.7, {bits: true}), '0.7 b');
+	t.is(prettyBytes(10, {bits: true}), '10 b');
+	t.is(prettyBytes(10.1, {bits: true}), '10.1 b');
+	t.is(prettyBytes(999, {bits: true}), '999 b');
+	t.is(prettyBytes(1001, {bits: true}), '1 kbit');
+	t.is(prettyBytes(1001, {bits: true}), '1 kbit');
+	t.is(prettyBytes(1e16, {bits: true}), '10 Pbit');
+	t.is(prettyBytes(1e30, {bits: true}), '1000000 Ybit');
+});