Answers for "check undefined in node js"

javascript check if not undefined

if (typeof myVar !== "undefined") {
    console.log("myVar is DEFINED");
}

how to check if object is undefined in javascript

if (typeof something === "undefined") {
    alert("something is undefined");
}

nodejs check if variable is undefined

if ( typeof query !== 'undefined' && query )
{
  //do stuff if query is defined and not null
}
else
{

}

undefined javascript check

if(undefinedElement === null) {
	console.log("Element is undefined");
}