is empty javascript code example

Example 1: is var is not blank then display value in javascript

if(data !== null && data !== '') {
   // do something
}

Example 2: javascript if string empty

// Test whether strValue is empty or is None
if (strValue) {
    //do something
}
// Test wheter strValue is empty, but not None 
if (strValue === "") {
    //do something
}

Example 3: empty string in javascript

var s; // undefined
var s = ""; // ""
s.length // 0

Example 4: empty javascript

function sum(a, a, c) { // !!! syntax error
  'use strict';
  return a + a + c; // wrong if this code ran
}

Example 5: empty javascript

'use strict';
delete Object.prototype; // throws a TypeError

Example 6: 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");
}