assign undefined to variable javascript code example
Example 1: javacript detect undefined
//detecting undefined object property
if (typeof person.last_name === "undefined") {
console.log("person last_name is undefined");
}
//detecting undefined variable
if (typeof myVar === "undefined") {
console.log("myVar is undefined");
}
Example 2: assign this value or if it is undefined this other value javascript
var x; //variable to change
var y; //higher priority variable
var z = 12; //lower priority variable
x = !(y === undefined) ? y : z;
console.log(x); //12