how to check javascript variable is empty or not code example

Example 1: javascript check if undefined or null or empty string

// simple check do the job
if (myString) {
 // comes here either myString is not null,
 // or myString is not undefined,
 // or myString is not '' (empty).
}

Example 2: javascript check if variable is empty

if( value ) {
  //
}

/**
* This will evaluate to true if value is not:
* null
* undefined
* NaN
* empty string ("")
* 0
* false
*/

Example 3: javascript check if empty

//check if string is undefined 
if (typeof myVar === 'undefined'){
  console.log("I am not defined");
}

//check if string is empty, null, or 0
var emptyString="";
if (emptyString) {
    console.log("im not empty");
}