JAVASCRIPT

hasOwnProperty

The hasOwnProperty() method returns a boolean indicating whether the object has the specified property as its own property (as opposed to inheriting it).

const object1 = {};
object1.property1 = 42;

console.log(object1.hasOwnProperty('property1'));
// expected output: true

console.log(object1.hasOwnProperty('toString'));
// expected output: false

hasownproperty javascript

//hasOwnPropertydevuelve un valor booleano que indica si el objeto al que está llamando tiene una propiedad con el nombre del argumento. Por ejemplo:

var x = {
y: 10};
console.log(x.hasOwnProperty("y")); //true
console.log(x.hasOwnProperty("z")); //false

hasownproperty

// JavaScript does not protect hasOwnProperty method
var foo = {
    // overriding foo's default hasOwnProperty method
    hasOwnProperty: function() {
        return false;
    },
    bar: 'data'
};
foo.hasOwnProperty('bar'); // false always

// Hence, to prevent this, use Object.prototype.hasOwnProperty as follows-
Object.prototype.hasOwnProperty.call(foo, 'bar'); // true

hasownproperty()

var x = {
    y: 10
};
console.log(x.hasOwnProperty("y")); //true
console.log(x.hasOwnProperty("z")); //false

hasOwnProperty

//
//2021 - Object.hasOwn as a replacement for Object.hasOwnProperty()

//As other answers indicated, hasOwnProperty will check for an object own properties in contrast to in which will also check for inherited properties.

//There is a new alternative method called Object.hasOwn() and is intended to be a replacement for Object.hasOwnProperty()**

const person = { name: 'dan' };

console.log(Object.hasOwn(person, 'name'));// true
console.log(Object.hasOwn(person, 'age'));// false

const person2 = Object.create({gender: 'male'});

console.log(Object.hasOwn(person2, 'gender'));// false
 Run code snippet