In JavaScript, Is There A Pre-defined Function To Verify If Variables Are Null, Undefined, Or Empty?

JavaScript does not have a built-in standard function to check for null, undefined, or blank variables. However, you can use a combination of conditional statements to achieve this kind of checking.

To check if a variable is null or undefined, you can use the strict equality operator (===) and compare the variable to null or undefined.


let myVar = null;

if (myVar === null || typeof myVar === 'undefined') {
  // variable is null or undefined

To check if a variable is blank (empty string), you can use the trim() method to remove leading and trailing whitespace characters and then check if the resulting string is empty.


let myVar = '';

if (myVar.trim() === '') {
  // variable is blank

Note that for the blank check, if you want to consider whitespace-only strings as non-blank, you can modify the condition accordingly.

Overall, it’s a good practice to perform separate checks for null/undefined and blank variables based on your specific requirements.

About the Author Rex

I'm a passionate tech blogger with an insatiable love for programming! From my early days tinkering with code, I've delved into web dev, mobile apps, and AI. Sharing insights and tutorials with the world is my joy, connecting me to a global community of like-minded tech enthusiasts. Python holds a special place in my heart, but I embrace all challenges. Constantly learning, I attend tech conferences, contribute to open-source projects, and engage in code review sessions. My ultimate goal is to inspire the next generation of developers and contribute positively to the ever-evolving tech landscape. Let's code together!