Properties of e: e.number: -2146823279 e.stack: ReferenceError: 'BadType' is undefined at throwException (propertyvalidation.js:65:9) at bar (propertyvalidation.js:85:5) at foo (propertyvalidation.js:90:5) at Global code (propertyvalidation.js:93:1) Deleting e.stack ... e.stack after delete: undefined Properties of e: e.number: -2146823279 e.stack: ReferenceError: 'BadType' is undefined at throwException (propertyvalidation.js:74:9) at bar (propertyvalidation.js:85:5) at foo (propertyvalidation.js:90:5) at Global code (propertyvalidation.js:93:1) Updating e.stack ... e.stack after update: foo Object.preventExtensions test: true true true true