if variable is empty in javascript code example

Example 1: javascript check if not null

//Even if the value is 0, this will execute. 

if (myVar !== null) {...}

//If you don't want it to execute when it's 0, then set it as

if (myVar) {...}

//This will return false if var value is 0.

Example 2: 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 3: javascript check if variable is empty

if( value ) {
  //
}

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