Send error message to client in node.js

I am getting an error on a async call to an api.

When I do console.log(err) it prints as below

{ [NOT_FOUND: Provided external ID field does not exist or is not accessible: sdds] name: 'NOT_FOUND', errorCode: 'NOT_FOUND' }

When I send this to client then this is seen

{"name":"NOT_FOUND","errorCode":"NOT_FOUND"}

I am unable to get this string on client

Provided external ID field does not exist or is not accessible: sdds

Which gets printed when I log it in node console.

Framework using is express, errorHandler node module.