check if object has key javascript es6 code example

Example 1: how to check if object has key javascript

myObj.hasOwnProperty('key') // it checks object for particular key and not on prototype

Example 2: 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 3: js object contain key

if ('key' in myObj)
// better
if (!myObj.hasOwnProperty('key'))

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: test if property exists javascript

const hero = {
  name: 'Batman'
};

hero.hasOwnProperty('name');     // => true
hero.hasOwnProperty('realName'); // => false

Example 6: typescript check if object has key

if ('key' in myObj)