use-object-hasown-to-check-properties-in-javascript.md

Use Object.hasOwn to check Object properties in JavaScript

The Object.hasOwn() is a modern JavaScript feature that allows you to check if a given property exists in an object. It's recommended over the Object.prototype.hasOwnProperty() function since it's safer and more intuitive

For example, if we have a custom object of a person:

const person = {
  name: 'John',
  age: 24,
  gender: 'male',
  bloodType: 'O',
};

We can use Object.hasOwn() function to check if the bloodType property is present in the person object:

Object.hasOwn(person, 'bloodType'); // true

The above example would have the same result as calling Object.proptype.hasOwnerProperty.call(person, 'bloodType');. However, Object.hasOwn() is much shorter and more convenient to use.

Here is another example of checking the property in a loop:

const people = [
  {
    name: 'Carly',
    yearOfBirth: 1942,
    yearOfDeath: 1970,
  },
  {
    name: 'Ray',
    yearOfBirth: 1962,
    yearOfDeath: 2011,
  },
  {
    name: 'Jane',
    yearOfBirth: 1912,
    yearOfDeath: 1941,
  },
  {
    name: 'Josh',
    yearOfBirth: 1933,
  },
];

const findTheOldest = (array) =>
  array.filter((person) => Object.hasOwn(person, 'yearOfDeath'));

console.log(findTheOldest(people));

References:

• Object.hasOwn() - MDN docs
• JavaScript: hasOwn() — new way to check if Object has property