function getUserDefinedLocale() {
	const locale = args['locale'];
	if (locale) {
		return Promise.resolve(locale.toLowerCase());
	}

	const localeConfig = path.join(userDataPath, 'User', 'locale.json');
	return bootstrap.readFile(localeConfig).then(content => {
		content = stripComments(content);
		try {
			const value = JSON.parse(content).locale;
			return value && typeof value === 'string' ? value.toLowerCase() : undefined;
		} catch (e) {
			return undefined;
		}
	}, () => {
		return undefined;
	});
}
function getUserDefinedLocale() {
	const locale = args['locale'];
	if (locale) {
		return Promise.resolve(locale.toLowerCase());
	}

	const localeConfig = path.join(userDataPath, 'User', 'locale.json');
	return bootstrap.readFile(localeConfig).then(content => {
		content = stripComments(content);
		try {
			const value = JSON.parse(content).locale;
			return value && typeof value === 'string' ? value.toLowerCase() : undefined;
		} catch (e) {
			return undefined;
		}
	}, () => {
		return undefined;
	});
}
function getUserDefinedLocale ( ) { const locale = args [ 'locale' ] ; if ( locale ) { return Promise . resolve ( locale . toLowerCase ( ) ) ; } const localeConfig = path . join ( userDataPath , 'User' , 'locale.json' ) ; return bootstrap . readFile ( localeConfig ) . then ( content => { content = stripComments ( content ) ; try { const value = JSON . parse ( content ) . locale ; return value && typeof value === 'string' ? value . toLowerCase ( ) : undefined ; } catch ( e ) { return undefined ; } } , ( ) => { return undefined ; } ) ; }
Language tags are case insensitive however an amd loader is case sensitive To make this work on case preserving & insensitive FS we do the following: the language bundles have lower case language tags and we always lower case the locale we receive from the user or OS. 
@returns {Promise<string>}
Language tags are case insensitive however an amd loader is case sensitive To make this work on case preserving & insensitive FS we do the following : the language bundles have lower case language tags and we always lower case the locale we receive from the user or OS .
Get the user defined locale