check if object is not undefined javascript 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: how to check if object is undefined in javascript

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

Example 4: checking if var is not defined js

if(typeof x !== 'undefined'){
  alert("Variable x is defined.");
}

Example 5: javascript check number against undefined

javascript check number against undefined