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

7

javascript if undefined

if(typeof comment === 'undefined') {

  alert('Variable "comment" is undefined.');

} else if(comment === null){

  alert('Variable "comment" is null.');

}
Posted by: Guest on March-25-2020
0

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
2

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 var is undefined in javascript"

Code answers related to "Javascript"

Browse Popular Code Answers by Language