Check If Property Exists Javascript Code Example

Example 1: How to tell if an attribute exists on an object

const user = {     name: "Sicrano",     age: 14 }  user.hasOwnProperty('name');       // Retorna true user.hasOwnProperty('age');        // Retorna true user.hasOwnProperty('gender');     // Retorna false user.hasOwnProperty('address');    // Retorna false

Example 2: how to check wether the property exist in a object in java script

if (obj.hasOwnProperty('prop')) {     // do something }

Example 3: check the properties of an object in javascript

for (var name in object) {       if (object.hasOwnProperty(name)) {          // do something with name                         }   }  // OR  const hero = {   name: 'Batman' };  hero.hasOwnProperty('name');     // => true hero.hasOwnProperty('realName'); // => false

Example 4: javascript does object have property

var person = {'first_name': 'bill','age':20};  if ( person.hasOwnProperty('first_name') ) {     //person has a first_name property }

Example 5: check if js property exists in class

myObj.hasOwnProperty(myProp)

Example 6: check if property exists javascript

// the coolest way const obj = {  weather: 'Sunny;  }  if('weather' in obj) {  // do something  }