/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

1 vote239 views1 answer
Node google client api to get user profile with already fetched token
Javascript Node.js
0 vote262 views1 answer
Node and bash together
Javascript Node.js
0 vote231 views1 answer
How to get datetime in nodejs
Javascript Node.js
3 votes331 views2 answers
Socket.io client send data node js server
Javascript Node.js
0 vote222 views1 answer
Nodejs response is html not json data
Javascript Node.js
0 vote212 views1 answer
How to load image from dir nodejs
Javascript Node.js
9 votes205 views2 answers
Microservices in node js
Javascript Node.js
0 vote221 views2 answers
Get audio duration node js
Javascript Node.js
1 vote229 views1 answer
Nodejs get response time
Javascript Node.js
-2 votes218 views1 answer
.env file make in nodejs
Javascript Node.js