js check undefined or empty code example

Example 1: javascript not null

if (variable !== null) {
  console.log("Var is NOT null");
}

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).
}