@stdlib/error-to-json NPM

error2json

Return a JSON representation of an error object.

Installation

npm install @stdlib/error-to-json

Usage

var error2json = require( '@stdlib/error-to-json' );

error2json( error )

Returns a JSON representation of an error object.

var err = new Error( 'beep' );

var json = error2json( err );
/* e.g., returns
    {
        'type': 'Error',
        'name': 'Error', // if present
        'message': 'beep',
        '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 = error2json( err );
/* e.g., returns
    {
        'type': 'Error',
        'name': 'Error', // if present
        'message': 'beep',
        'stack': '...', // if present
        'a': 'b',
        'c': {
            'd': 'e'
        }
    }
*/

Notes

Supported built-in error types:

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 = error2json( err );
/* e.g., returns
    {
        'type': 'TypeError',
        'name': 'CustomError',
        'message': 'boop',
        'stack': '...'
    }
*/

Examples

var error2json = require( '@stdlib/error-to-json' );

var err = new Error( 'beep' );
var out = error2json( err );
/* e.g., returns
    {
        'type': 'Error',
        'name': 'Error',
        'message': 'beep',
        'stack': '...'
    }
*/

err = new TypeError( 'invalid type' );
out = error2json( err );
/* e.g., returns
    {
        'type': 'TypeError',
        'name': 'TypeError',
        'message': 'invalid type',
        'stack': '...'
    }
*/

err = new SyntaxError( 'bad syntax' );
out = error2json( err );
/* e.g., returns
    {
        'type': 'SyntaxError',
        'name': 'SyntaxError',
        'message': 'bad syntax',
        'stack': '...'
    }
*/

err = new ReferenceError( 'unknown variable' );
out = error2json( err );
/* e.g., returns
    {
        'type': 'ReferenceError',
        'name': 'ReferenceError',
        'message': 'unknown variable',
        'stack': '...'
    }
*/

err = new URIError( 'bad URI' );
out = error2json( err );
/* e.g., returns
    {
        'type': 'URIError',
        'name': 'URIError',
        'message': 'bad URI',
        'stack': '...'
    }
*/

err = new RangeError( 'value out-of-range' );
out = error2json( err );
/* e.g., returns
    {
        'type': 'RangeError',
        'name': 'RangeError',
        'message': 'value out-of-range',
        'stack': '...'
    }
*/

err = new EvalError( 'eval error' );
out = error2json( err );
/* e.g., returns
    {
        'type': 'EvalError',
        'name': 'EvalError',
        'message': 'eval error',
        'stack': '...'
    }
*/

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.