/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

16 votes114 views2 answers
How to create an array in node js
Javascript Node.js
112 votes217 views6 answers
Node js install ubuntu
Javascript Node.js
0 vote115 views1 answer
How to get file tree of specific folder in node js
Javascript Node.js
0 vote95 views1 answer
Nodejs validate bnb wallet address
Javascript Node.js
1 vote118 views1 answer
Jwt token expire time in node js
Javascript Node.js
0 vote119 views1 answer
What is amqp10 policy nodejs
Javascript Node.js
-4 votes113 views5 answers
Nodejs
Javascript Node.js
5 votes123 views1 answer
Install node js 14
Javascript Node.js
1 vote103 views1 answer
Data not write in file node js
Javascript Node.js
3 votes96 views3 answers
Node get current url
Javascript Node.js