Answers for "how to check if variable in javascript is undefined"

test if is undefined javascript

let id;

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

Posted by: Guest on August-10-2020

nodejs check if variable is undefined

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

}

Posted by: Guest on December-25-2020

js check if undefined

let foo = undefined
//will return true
typeof foo === 'undefined'

Posted by: Guest on July-15-2020

Code answers related to "how to check if variable in javascript is undefined"