Websql callbacks vs Sqlite callbacks

In ionic2 RC1, I am using the solution of websql on browsers and sqlite on real devices, My problem is the transaction callbacks success and fail, They are reversed on the browser fail called instead of success and vice versa.

db.transaction((tx: any) => {
let vals, sql;
tx.executeSql(sql, vals, undefined, fail);

},success , fail);

on real devices success is called on success cases and fail is called on failure, but on browser fail is called for success and success is called on failure !!!11

Am i misunderstood something ?
Anyone can help in this ?

any help in this issue ?