how to check a string is empty in angularjs

Question

I am checking a value in my controller.Here is my code.

var contents = atob(response.documents);
// I checked the value in contents . it is displaying ""
if(contents === ""){
 // no contents
}

the if condition is retuning false, when the contents has "" and when the contents has data. How to check condition?

Answer 1

Good plain Javascript.

if(!contents){

}

Answer 2

How about contents.trim().length === 0 ?

Answer 3

Empty string in Javascript is falsey you can use:

if(contents){
  //has content
}else{
 //no content
}