Throw better errors

[jksdua]

Adding a placeholder for updating errors thrown by js-quantities.

Preferably, an instance of Error should be thrown so users can handle them as they usually would other errors.

Additionally, it would be nice to have the args passed to the function printed as part of the message so that there is enough information in the message to be able to debug the issue.

If you agree, I'll send a pull request.

Thanks for the port, the library is great!

Cheers, Jaap

[gentooboontoo]

@jksdua, it sounds like a good idea. I would be glad to merge a pull request from you.

What do you think about implementing a custom Error type QtyError like the following code?

function QtyError() {
  var err = Error.apply(this, arguments);
  this.name = 'QtyError';
  this.message = err.message;
  this.stack = err.stack;
}
QtyError.prototype = Object.create(Error.prototype, {constructor: { value: QtyError }});

It would be semantically correct (This error would be instanceof Error and QtyError).

try {
  .... // Something throwing QtyError instances
}
catch(e) {
  if(e instanceof QtyError) {
    ....
  }
}

[jksdua]

Sounds good. I'll send a pull request on the weekend.