add tests and docs

index.d.ts

@@ -17,6 +17,14 @@ declare namespace prettyBytes {
 		@default false
 		*/
 		readonly locale?: boolean | string;
+
+		/**
+		Display proper units for bits.
+
+		@default false
+		*/
+
+		readonly bits?: boolean;
 	}
 }
 
@@ -42,6 +50,10 @@ prettyBytes(42, {signed: true});
 // Localized output using German locale
 prettyBytes(1337, {locale: 'de'});
 //=> '1,34 kB'
+
+// Display with units of bits
+prettyBytes(1337, {bits: true});
+// => '1,34 kbit'
 ```
 */
 declare function prettyBytes(

index.js

@@ -47,13 +47,12 @@ module.exports = (number, options) => {
 	}
 
 	options = Object.assign({}, options);
+	const UNITS = options.bits === true ? BIT_UNITS : BYTE_UNITS;
 
 	if (options.signed && number === 0) {
-		return ' 0 B';
+		return ' 0 ' + UNITS[0];
 	}
 
-	const UNITS = options.bits !== true ? BYTE_UNITS : BIT_UNITS;
-
 	const isNegative = number < 0;
 	const prefix = isNegative ? '-' : (options.signed ? '+' : '');
 
@@ -63,7 +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

@@ -33,6 +33,10 @@ prettyBytes(42, {signed: true});
 // Localized output using German locale
 prettyBytes(1337, {locale: 'de'});
 //=> '1,34 kB'
+
+// Display with units of bits
+prettyBytes(1337, {bits: true});
+// => '1,34 kbit'
 ```
 
 
@@ -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`
+
+Treat input as bits and use proper units respectively.
 
 ##### 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');
+});