utils-error-to-json

toJSON

Returns a JSON representation of an error object.

Installation

$ npm install utils-error-to-json

Usage

var toJSON = require( 'utils-error-to-json' );

toJSON()

Returns a JSON representation of an error object.

var err = new Error( 'beep' );
 
var json = toJSON( err );
/*
  {
    "type": "Error",
    "name": "Error", // if present
    "message": "beep",
    "stack": "<stack>" // if present
  }
*/

The JSON object is guaranteed to have the following properties:

• type: error type
• message: error message

The only standardized cross-platform property is message. Depending on the platform, the following properties may be present:

• name: error name
• stack: stack trace
• code: error code (Node.js system errors)
• errno: error code string (Node.js system errors)
• syscall: string representing the failed system call (Node.js system errors)

The function also serializes all enumerable properties.

var err = new Error( 'beep' );
err.a = 'b';
err.c = { 'd': 'e' };
 
var json = toJSON( err );
/*
  {
    "type": "Error",
    "name": "Error", // if present
    "message": "beep",
    "stack": "<stack>", // if present
    "a": "b",
    "c": {
      "d": "e"
    }
  }
*/

Notes

• Supported built-in error types:

  • Error
  • TypeError
  • SyntaxError
  • ReferenceError
  • RangeError
  • URIError
  • EvalError

• The implementation supports custom error types and sets the type field to the closest built-in error type.

  function CustomError( msg ) {
      this.name = 'CustomError';
      this.message = msg || '';
      this.stack = ( new TypeError() ).stack;
      return this;
  }
  CustomError.prototype = Object.create( TypeError.prototype );
  CustomError.prototype.constructor = CustomError;
   
  var err = new CustomError( 'boop' );
   
  var json = toJSON( err );
  /*
    {
      "type": "TypeError",
      "name": "CustomError", 
      "message": "boop",
      "stack": "<stack>"
    }
  */

Examples

var toJSON = require( 'utils-error-to-json' );
 
var err = new Error( 'beep' );
console.log( toJSON( err ) );
/*
  {
    "type": "Error",
    "name": "Error",
    "message": "beep",
    "stack": "<stack>"
  }
*/
 
err = new TypeError( 'invalid type' );
console.log( toJSON( err ) );
/*
  {
    "type": "TypeError",
    "name": "TypeError",
    "message": "invalid type",
    "stack": "<stack>"
  }
*/
 
err = new SyntaxError( 'bad syntax' );
console.log( toJSON( err ) );
/*
  {
    "type": "SyntaxError",
    "name": "SyntaxError",
    "message": "bad syntax",
    "stack": "<stack>"
  }
*/
 
err = new ReferenceError( 'unknown variable' );
console.log( toJSON( err ) );
/*
  {
    "type": "ReferenceError",
    "name": "ReferenceError",
    "message": "unknown variable",
    "stack": "<stack>"
  }
*/
 
err = new URIError( 'bad URI' );
console.log( toJSON( err ) );
/*
  {
    "type": "URIError",
    "name": "URIError",
    "message": "bad URI",
    "stack": "<stack>"
  }
*/
 
err = new RangeError( 'value out-of-range' );
console.log( toJSON( err ) );
/*
  {
    "type": "RangeError",
    "name": "RangeError",
    "message": "value out-of-range",
    "stack": "<stack>"
  }
*/
 
err = new EvalError( 'eval error' );
console.log( toJSON( err ) );
/*
  {
    "type": "EvalError",
    "name": "EvalError",
    "message": "eval error",
    "stack": "<stack>"
  }
*/

To run the example code from the top-level application directory,

$ node ./examples/index.js

---

Tests

Unit

This repository uses tape for unit tests. To run the tests, execute the following command in the top-level application directory:

$ make test

All new feature development should have corresponding unit tests to validate correct functionality.

Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

$ make test-cov

Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

$ make view-cov

Browser Support

This repository uses Testling for browser testing. To run the tests in a (headless) local web browser, execute the following command in the top-level application directory:

$ make test-browsers

To view the tests in a local web browser,

$ make view-browser-tests

---

License

MIT license.

Copyright

Copyright © 2015. Athan Reines.