/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

0 vote127 views1 answer
Isodate mongodb nodejs
Javascript Node.js
1 vote131 views1 answer
Nodejs chaning env variable at runtime
Javascript Node.js
0 vote132 views1 answer
Nodejs get appdata path
Javascript Node.js
1 vote127 views1 answer
Node wait 10 seconds
Javascript Node.js
13 votes142 views4 answers
Node version manager install
Javascript Node.js
0 vote125 views1 answer
Node http2 post
Javascript Node.js
-1 vote133 views3 answers
Stripe subscription node js
Javascript Node.js
0 vote124 views2 answers
Ubuntu 18.04 nodejs insatll
Javascript Node.js
0 vote129 views1 answer
Nodejs add new property array object
Javascript Node.js
0 vote129 views1 answer
Node sudo nvm
Javascript Node.js