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javascriptnode.jserror-handlingtry-catch

javascript node.js getting line number in try catch?


I'm using try catch on a node.js script:

try {} catch (err) {console.log(err)}

I get an output like this:

{ 
  stack: [Getter/Setter],
  arguments: [ 'undefined' ],
  type: 'called_non_callable',
  message: [Getter/Setter]
}

Is there an easy way to make this more informative? Include line numbers and function names and such?


Solution

  • Those [Getter/Setter] members indicate further information available on the error object. You can easily dump the contents of those getters/setters using a small helper function (very trivial implementation, further refinement is up to you)

    function dumpError(err) {
      if (typeof err === 'object') {
        if (err.message) {
          console.log('\nMessage: ' + err.message)
        }
        if (err.stack) {
          console.log('\nStacktrace:')
          console.log('====================')
          console.log(err.stack);
        }
      } else {
        console.log('dumpError :: argument is not an object');
      }
    }
    
    try {
      not_defined.function_call();
    } catch(err) {
      dumpError(err);
    }
    

    You could also extend the Object.prototype for improved accessibility (so you could use err.dumpError()), although extending Object.prototype bears the risk of overwriting existing functionality.