What is a closure in JavaScript? Provide an example.

Question

Ravi Vishwakarma · Answer

A closure in JavaScript is a feature where an inner function has access to its outer (enclosing) function's variables even after the outer function has finished executing. Closures are created whenever a function is created, allowing the function to remember the scope in which it was created.
Key Characteristics of Closures:
Access to Outer Function’s Variables: The inner function can access variables and parameters of its outer function even after the outer function has returned.Private Data: Closures can be used to create private variables or methods.
and 
Example of a Closure:
function outerFunction() {
 let outerVariable = 'I am an outer variable';
 function innerFunction() {
 console.log(outerVariable); // Can access the outer variable
 }
 return innerFunction;
}
const closure = outerFunction(); // outerFunction returns innerFunction, which has a reference to outerVariable
closure(); // Logs: 'I am an outer variable'
In this example:
outerFunction declares a variable outerVariable and defines an
innerFunction.innerFunction has access to outerVariable because it is within the scope of
outerFunction.When outerFunction is called, it returns innerFunction. The
innerFunction maintains access to outerVariable even after
outerFunction has completed execution.Calling closure() (which is the returned innerFunction) logs the value of
outerVariable.
and 
Practical Example :
andlt;script type="text/javascript">
	function createCounter() {
	 let count = 0; // Private variable
	 return {
	 increment: function() {
	 count++;
	 return count;
	 },
	 decrement: function() {
	 count--;
	 return count;
	 },
	 getCount: function() {
	 return count;
	 }
	 };
	}
	const counter = createCounter();
	console.log(counter.increment()); 
	console.log(counter.increment()); 
	console.log(counter.decrement()); 
	console.log(counter.getCount()); 
	console.log(counter.count); 
andlt;/script>
Output:
and

interview

What is a closure in JavaScript? Provide an example.

Ravi Vishwakarma

1 Answers

Key Characteristics of Closures:

Liked By