fix: improve error item message for plain objects (#286)

Fixes: #252

Author: DominicKramer

src/populate-error-message.ts

@@ -16,6 +16,7 @@
 
 import * as is from 'is';
 import has = require('lodash.has');
+import * as util from 'util';
 
 import {buildStackTrace} from './build-stack-trace';
 import {ErrorMessage} from './classes/error-message';
@@ -109,7 +110,7 @@ function populateFromObject(ob: PopulatedObject, errorMessage: ErrorMessage) {
   if (has(ob, 'message')) {
     errorMessage.setMessage(ob.message!);
   } else {
-    errorMessage.setMessage(buildStackTrace('' + ob));
+    errorMessage.setMessage(buildStackTrace(util.inspect(ob)));
   }
 
   if (has(ob, 'user')) {

system-test/error-reporting.ts

@@ -630,7 +630,7 @@ describe('error-reporting', () => {
      async function(this) {
        this.timeout(TIMEOUT);
        await verifyReporting({someKey: 'someValue'}, message => {
-         return message.startsWith('[object Object]\n');
+         return message.startsWith('{ someKey: \'someValue\' }\n');
        }, 1, TIMEOUT);
      });
 

test/unit/populate-error-message.ts

@@ -114,9 +114,9 @@ describe('populate-error-message', () => {
   it('Message Field: Should default the field given lack-of input given ' +
          'an object',
      () => {
-       const err = {};
+       const err = {error: 'some error message'};
        populateErrorMessage(err, em);
-       assert(em.message.startsWith('[object Object]'));
+       assert(em.message.startsWith('{ error: \'some error message\' }'));
      });
 
   it('User Field: Should set the field given valid input given an Error',