Lecture 138:- Function within Function

A function defined inside another function is called a nested function or an inner function.

Inner functions have access to the variables and parameters of the outer function. This is called "lexical scoping" or "closure". The inner function can use these variables even after the outer function has returned.

Here's an example:

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function outerFunction(x) {  function innerFunction(y) {    return x + y;  }  return innerFunction; } var newFunction = outerFunction(4); console.log(newFunction(3)); // Output: 7

In this example, outerFunction returns innerFunction, and assigns it to newFunction. When newFunction is invoked with an argument of 3, it returns the sum of x (which is 4) and y (which is 3), resulting in 7.

Note that x is defined in outerFunction, but innerFunction has access to it due to closure.