Writing thrown errors to a file in Javascript

Question

Is there a way to add a default behavior in javascript to the throw event. Like I am trying to add to a file whenever an error is thrown :

Example :

 if (tables.length === 0) {
      throw new Error("NO_TABLES_RETRIEVED");
    }

I want to write to file first and then throw the error. I know I can add a function and just before throwing I can call that function but just to know more is there something like to add a default behavior with throw?

Answer 1

Error is different from Exception in Javascript w.r.t NodeJS. An error is any instance of the Error class. Errors may be constructed and then passed directly to another function or thrown. When you throw an error, it becomes an exception.2 Here's an example of using an error as an exception:

throw new Error('something bad happened');

but you can just as well create an Error without throwing it:

callback(new Error('something bad happened'));

Since you mentioned in the comment that you don't want to require the error handler file in all the files of the app. You can also make use of NodeJS EventEmitter module or use a error handler middleware