JavaScript: hasOwn() — nova maneira de verificar se o objeto tem propriedade

1. inoperador
2. hasOwnProperty()função

const developer = { 
  age: 32
};

'age' in developer; // true

developer.hasOwnProperty('age'); // true

'constructor' in developer; // true

developer.hasOwnProperty('constructor'); // false

1. hasOwnPropertypode ser substituído:

var developer = {
  age: 32, 
  hasOwnProperty: "frontend"
};

developer.hasOwnProperty('age') // throws a TypeError

var developer = Object.create(null);
someObject.hasOwnProperty('age'); // throws a TypeError

/* not recommended */
const hasBarProperty = developer.hasOwnProperty("age");

/* recommended */
const hasBarProperty = Object.prototype.hasOwnProperty.call(developer, "age");

const developer = { 
  age: 32
};

Object.hasOwn(developer, 'age') // true

Object.hasOwn(developer, 'not-existing-property'); // false

Object.hasOwn(developer, 'constructor'); // false

developer.hasOwnProperty = () => false;

developer.hasOwnProperty('age'); // false

Object.hasOwn(developer, 'age') // true

Object.prototype.hasOwnProperty.call(developer, 'age'); // true

Object.hasOwn(developer, 'age'); // true