Javascript retrieving error name and message from Error() object

Question

I throw an Error using the Error() object in a simplified function like so:

function errorExample() {
  try {
    throw new Error('ConnectionError', 'cannot connect to the internet')
  }
  catch(error) {
    console.log(error
  }
}

I want to be able to access the error name and message from within the catch statement.

According to Mozilla Developer Network I can access them through error.proptotype.name and error.proptotype.message however with the code above I receive undefined.

Is there a way to do this? Thanks.

See custom error types @ MDN if you want your own name.

Alex K.
– Alex K.

2017-02-23 19:09:56 +00:00
Commented Feb 23, 2017 at 19:09 — Alex K.
– Alex K., Commented Feb 23, 2017 at 19:09

SLaks · Accepted Answer · 2017-02-23 19:08:45Z

4

You're misreading the documentation.

Fields on Error.prototype exist on all Error instances. Since error is an instance of the Error constructor, you can write error.message.

answered Feb 23, 2017 at 19:08

SLaks

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Comments

Austin France · Accepted Answer · 2017-02-23 19:26:53Z

2

By default, the name of an error is 'Error', you can override it:

function errorExample() {
  try {
    var e = new Error('cannot connect to the internet');
    e.name = 'ConnectionError';
    throw e;
  }
  catch(error) {
    console.log(error.name);
    console.log(error.message);
  }
}

See: Error.prototype.name

edited Feb 23, 2017 at 19:26

answered Feb 23, 2017 at 19:21

Austin France

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Comments

iLearn · Accepted Answer · 2017-02-23 19:30:10Z

0

Try this

function errorExample() {
  try {
    throw new Error('ConnectionError', 'cannot connect to the internet');
  }
  catch(error) {
    console.log(error.message);
    console.log(error.name);
  }
}
errorExample() ;

edited Feb 23, 2017 at 19:30

answered Feb 23, 2017 at 19:21

iLearn

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