Throw new Error or WinJS.Promise.wrapError() - what's recommended?

Question

What are the implications of both? Does it make any difference if I re-throw an error from within a Promises error handler or return a WinJS.Promise.wrapError from the error handler?

Answer 1

Still haven't figured this one out. Should we use wrapError in code like this:

return doo.data.withDatabase(function(db) {
      return db.oneAsync("SELECT something from a table WHERE path=?", [path]).then(function(result) {
        if (result) {
          futureAccessList.remove(result.token);
          return db.runAsync("DELETE FROM WatchedFolders WHERE id=?", [result.id]);
        }
      });
    })

At the point where result is checked, should I use wrapError(new Error("Not found")) or just throw new Error("Not found")?

Answer 2

It depends on what you need to do with the promise.  Docs say this is the point of wrapError:

Wraps a non-promise error value in a promise. You can use this function if you need to pass an error to a function that requires a promise.

If you need to pass an error to a function that requires a promise, then that's what you need.  If you're handling the error otherwise, then you don't need this function. 

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Matt Small - Microsoft Escalation Engineer - Forum Moderator
If my reply answers your question, please mark this post as answered.

NOTE: If I ask for code, please provide something that I can drop directly into a project and run (including XAML), or an actual application project. I'm trying to help a lot of people, so I don't have time to figure out weird snippets with undefined objects and unknown namespaces.