/Javascript/Node.js/Nodejs check if variable is undefined

Nodejs check if variable is undefined

Javascript check if not undefined

if (typeof myVar !== "undefined") {
    console.log("myVar is DEFINED");
}

Javascript if undefined

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

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

} else if(comment === null){

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

}

Source: tutorialrepublic.com

Js check if undefined

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

Nodejs check if variable is undefined

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

}

Source: stackoverflow.com

Similar codes

5 votes229 views2 answers
Install ejs nodejs
Javascript Node.js
-3 votes251 views3 answers
Node qrcode
Javascript Node.js
17 votes268 views3 answers
Await in node js
Javascript Node.js
-1 vote228 views2 answers
Where to create service angularor nodejs
Javascript Node.js
0 vote214 views1 answer
Node pg array in
Javascript Node.js
1 vote221 views1 answer
Node js util promisify
Javascript Node.js
6 votes219 views3 answers
Get random number node js
Javascript Node.js
9 votes215 views6 answers
Node js
Javascript Node.js
0 vote200 views1 answer
Orm for postgres node js
Javascript Node.js
1 vote196 views1 answer
What is the meanof using next in nodejs
Javascript Node.js