serialize-error 
Serialize an error into a plain object
Useful if you for example need to JSON.stringify() or process.send() the error.
Install
$ npm install --save serialize-error
Usage
const serializeError = require('serialize-error');
const error = new Error('unicorn');
console.log(error);
//=> [Error: unicorn]
console.log(serializeError(error));
//=> {name: 'Error', message: 'unicorn', stack: 'Error: unicorn\n at Object.<anonymous> ...'}
License
MIT © Sindre Sorhus