/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 vote187 views1 answer
“new Set” is returning an empty set in nodejs
Javascript Node.js
1 vote182 views2 answers
Create file if not exists nodejs
Javascript Node.js
0 vote177 views1 answer
Node scheduler rules
Javascript Node.js
0 vote185 views1 answer
Filewatcher nodejs
Javascript Node.js
0 vote164 views1 answer
Node js validate body without middleware
Javascript Node.js
-2 votes173 views1 answer
Scraping google nodejs
Javascript Node.js
62 votes338 views6 answers
Update nodejs ubuntu
Javascript Node.js
0 vote185 views1 answer
How to check if a folder exists in node js
Javascript Node.js
0 vote159 views1 answer
Node sass how to configure number of spaces
Javascript Node.js
0 vote157 views1 answer
Exit application node js
Javascript Node.js