JAVASCRIPT

javascript check if undefined or null

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

js if not undefined or null

if(variable == null) //variable is undefined or null

check null or undefined in javascript

//check for null or undefined with nullish coalescing operator
let value = null ?? "Oops.. null or undefined";

console.log(value) //Oops.. null or undefined

value = 25 ?? "Oops.. null or undefined";

console.log(value) // 25

value = "" ?? "Oops.. null or undefined";

console.log(value) // ""

javascript check undefined or null

var myVar=null;

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

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

javascript check if undefined or null

// simple check do the job
if (myVar) {
 // comes here either myVar is not null,
 // or myVar is not undefined,
 // or myVar is not '' (empty string).
}