Object has a given property

property.js

var ferObject = {
  name: 'Todd',
  favouriteDrink: null,
  cool: false
};

!!ferObject.name            //true
!!ferObject.favouriteDrink  //false
!!ferObject.cool            //false
!!ferObject.cools           //false

ferObject.hasOwnProperty('name')            //true
ferObject.hasOwnProperty('favouriteDrink')  //true
ferObject.hasOwnProperty('cool')            //true
ferObject.hasOwnProperty('cools')           //false

function hasProp (obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

hasProp(ferObject, 'name')           //true
hasProp(ferObject, 'favouriteDrink') //true
hasProp(ferObject, 'cool')           //true
hasProp(ferObject, 'cools')          //false

'name' in ferObject           //true
'favouriteDrink' in ferObject //true
'cool' in ferObject           //true
'cools' in ferObject          //false