Switch from underscore to dash for the locale: en_US → en-US

Fixes #30

Author: sindresorhus

index.d.ts

@@ -21,7 +21,7 @@ declare const osLocale: {
 
 	(async () => {
 		console.log(await osLocale());
-		//=> 'en_US'
+		//=> 'en-US'
 	})();
 	```
 	*/

index.js

@@ -4,7 +4,7 @@ const lcid = require('lcid');
 const mem = require('mem');
 
 const defaultOptions = {spawn: true};
-const defaultLocale = 'en_US';
+const defaultLocale = 'en-US';
 
 function getEnvLocale(env = process.env) {
 	return env.LC_ALL || env.LC_MESSAGES || env.LANG || env.LANGUAGE;
@@ -24,7 +24,7 @@ function getLocale(string) {
 	return (string && string.replace(/[.:].*/, ''));
 }
 
-function getLocales() {
+async function getLocales() {
 	return execa.stdout('locale', ['-a']);
 }
 
@@ -81,37 +81,37 @@ function getWinLocaleSync() {
 }
 
 const osLocale = mem(async (options = defaultOptions) => {
-	const envLocale = getEnvLocale();
-
+	let locale;
 	try {
-		let locale;
+		const envLocale = getEnvLocale();
+
 		if (envLocale || options.spawn === false) {
 			locale = getLocale(envLocale);
 		} else if (process.platform === 'win32') {
 			locale = await getWinLocale();
 		} else {
 			locale = await getUnixLocale();
 		}
+	} catch (_) {}
 
-		return locale || defaultLocale;
-	} catch (_) {
-		return defaultLocale;
-	}
+	return (locale || defaultLocale).replace(/_/, '-');
 });
 
 module.exports = osLocale;
 
 module.exports.sync = mem((options = defaultOptions) => {
-	const envLocale = getEnvLocale();
-
-	let result;
-	if (envLocale || options.spawn === false) {
-		result = getLocale(envLocale);
-	} else {
-		try {
-			result = process.platform === 'win32' ? getWinLocaleSync() : getUnixLocaleSync();
-		} catch (_) {}
-	}
+	let locale;
+	try {
+		const envLocale = getEnvLocale();
+
+		if (envLocale || options.spawn === false) {
+			locale = getLocale(envLocale);
+		} else if (process.platform === 'win32') {
+			locale = getWinLocaleSync();
+		} else {
+			locale = getUnixLocaleSync();
+		}
+	} catch (_) {}
 
-	return result || defaultLocale;
+	return (locale || defaultLocale).replace(/_/, '-');
 });

readme.md

@@ -34,7 +34,7 @@ const osLocale = require('os-locale');
 
 (async () => {
 	console.log(await osLocale());
-	//=> 'en_US'
+	//=> 'en-US'
 })();
 ```
 

test.js

@@ -3,7 +3,7 @@ import test from 'ava';
 import importFresh from 'import-fresh';
 
 const envVars = ['LC_ALL', 'LANGUAGE', 'LANG', 'LC_MESSAGES'];
-const expectedFallback = 'en_US';
+const expectedFallback = 'en-US';
 
 function unsetEnvVars(cache) {
 	for (const envVar of envVars) {
@@ -26,14 +26,14 @@ test('async', async t => {
 	const locale = await importFresh('.')();
 	console.log('Locale identifier:', locale);
 	t.true(locale.length > 1);
-	t.true(locale.includes('_'));
+	t.true(locale.includes('-'));
 });
 
 test('sync', t => {
 	const locale = importFresh('.').sync();
 	console.log('Locale identifier:', locale);
 	t.true(locale.length > 1);
-	t.true(locale.includes('_'));
+	t.true(locale.includes('-'));
 });
 
 test('async without spawn', async t => {