How to use `hasOwn()` to check if an object has a specific property?

const transformer = {
  fraction: 'Autobots',
  hasOwnProperty() {
    return 'Decepticons!';
  },
};

// output: 'Decepticons'
console.log(transformer.hasOwnProperty('fraction'));
// output: true
console.log(Object.hasOwn(transformer, 'hasOwnProperty'));

Copy

August 5th, 2022

# Check if an object has a specific property

A safe way to check if an object has a specific property, is to use Object.hasOwn. It is possible to do the same with Object.prototype.hasOwnProperty, but the problem is, that the object could have it's own proerty named hasOwnProperty.

Tracking with Matomo to improve the UX. See Privacy Policy for more details.

Snippets

Highlight all images without alt attribute

unshift() - Add element to start of an array

Primitive types in Javascript

map() - Applying a function to every element of an array

Functional Component

Custom bullet points

for...of - Looping an array

Template Literals

Javascript Closure

for...in - Looping an array

Object literal

Multiple ways of creating arrays

Parallax images on scroll with CSS

Creating an object out of an array

Sticky footer with CSS

componentDidUpdate() as hook

forEach() - Looping an array

Padding bottom trick

componentWillUnmount() as hook

componentDidMount() as hook

# Check if an object has a specific property