nodejs check null or empty code example

Example 1: javascript check for null variables

var myVar=null;

if(myVar === null){
    //I am null;
}

if (typeof myVar === 'undefined'){
    //myVar is undefined
}

Example 2: how to check is null or empty in typescript

if(typeof propertyValue!='undefined' && propertyValue){
	//execute code here
}