nodejs check if value is undefined code example

Example 1: js if not undefined

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

Example 2: test if is undefined javascript

let id;

if(typeof id === 'undefined') {
    console.log("id is undefined...");
}

Example 3: undefined javascript check

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

Example 4: How can I check whether a variable is defined in Node Js

if (query){
   doStuff();
}