Async read and write keys

lib/storages/fsKeysStorage.js

@@ -6,14 +6,24 @@ module.exports = (pathToFile) => {
 	const path = pathToFile;
 
 	return {
-		read() {
-			if (!fs.existsSync(path))
-				return null;
-			return fs.readFileSync(path, { encoding: 'utf8' });
+		write(data) {
+			return new Promise((resolve, reject) => {
+				fs.writeFile(path, data, { encoding: 'utf8' }, (error) => {
+					if (error) throw error;
+
+					return resolve();
+				});
+			});
 		},
 
-		write(data) {
-			fs.writeFileSync(path, data, { encoding: 'utf8' });
+		read() {
+			return new Promise((resolve, reject) => {
+				fs.readFile(path, { encoding: 'utf8' }, (error, data) => {
+					if (error) reject(error);
+
+					return resolve(data);
+				});
+			});
 		},
 	};
 };