how to check if a json object has a key in javascript code example

Example 1: forjs check if key in json

var json = {key1: 'value1', key2: 'value2'}

"key1" in json ? console.log('key exists') : console.log('unknown key')

"key3" in json ? console.log('key exists') : console.log('unknown key')

Example 2: check if json obj exists

if(thisSession.hasOwnProperty('merchant_id')){

}