Enumerate properties that will not enumerate in older browsers (i.e. IE 8 and below).

npm install enum-bug

Note: use add --save if you are using npm < 5.0.0

import enumBug from 'enum-bug';

const obj = {
  hello: 'not a bugged property',
  constructor: 'bugged property',
  hasOwnProperty: 'bugged property',
  isPrototypeOf: 'bugged property',
  propertyIsEnumerable: 'bugged property',
  toLocaleString: 'bugged property',
  toString: 'bugged property',
  valueOf: 'bugged property',
  goodbye: 'another normally enumerated property',
};

enumBug(obj, prop => {
  console.log(`${prop} is bugged.`);
});

By executing the code in an environment that contains an object enumeration bug (i.e. Internet Explorer 8 and below), the result will be

// console
 => constructor is bugged
 => hasOwnProperty is bugged
 => isPrototypeOf is bugged
 => propertyIsEnumerable is bugged
 => toLocaleString is bugged
 => toString is bugged
 => valueOf is bugged

The bugged properties are:

• constructor
• hasOwnProperty
• isPrototypeOf
• propertyIsEnumerable
• toLocaleString
• toString
• valueOf

This module will only enumerate over bugged properties in environments where they would not otherwise be enumerated.

If the environment enumerates object properties properly, then no properties are enumerated.