new promise wrapping example

new_promise.js

const methodReturningPromise = () => {
  return new Promise((resolve, reject) => {
    asyncMethodToFetchData(params, (err,result) => {
      if(err){
        reject(err); // return rejected promise to method caller
      };
      else{
        resolve(result); // return fulfilled promise to method caller
      }
    });
  });    
}