JAVASCRIPT

javascript nested functions

/*
 * A nested function is a function within another function.
 * A nested function is local, meaning it can only be accessed
 * by code within that same function scope.
 */
function globalFunction() {
	function localFunction() {
		return "Hello world!";
	}
	return localFunction();
}
console.log(globalFunction()); // -> "Hello world!"
console.log(localFunction()); // -> Uncaught ReferenceError: localFunction is not defined

nested function javascript

/*
Function Syntax:
function functionName(parameter1, parameter2, ...) {
	return something;
}
*/

function globalFunction(a, b, c) {
	// `localFunction` cannot be called outside of `globalFunction`, once `globalFunction` finishes, `localFunction` ceases to exist
	function localFunction(d, e, f) {
		return [ f, e, d ];
	}
	return localFunction(a, b, c);
}

JavaScript Nested Function

// nested function example

// outer function
function greet(name) {

    // inner function
    function displayName() {
        console.log('Hi' + ' ' + name);
    }

    // calling inner function
    displayName();
}

// calling outer function
greet('John'); // Hi John