Replace a value if null or undefined in JavaScript?

To replace a value if null or undefined, you can use below syntax −

var anyVariableName= null;
var anyVariableName= yourVariableName|| anyValue;

Example

var value = null;
console.log("The value ="+value)
var actualValue = value || "This is the Correct Value";
console.log("The value="+actualValue);

To run the above program, you need to use the following command −

node fileName.js.

Here, my file name is demo56.js

Output

This will produce the following output −

PS C:\Users\Amit\JavaScript-code> node demo56.js
The value =null
The value=This is the Correct Value