Scope and Functions

foreach.js

function forEach(arr, fn){
	for(var i = 0; i < arr.length; ++i){
		var value = arr[i];
		fn(value);
	}
}

forEach([0, 1, 2], function(val){
	console.log(`I ate ${val} hamburgers`);
})

function map(arr, transform){
	var newArray = [];
	for(var i = 0; i < arr.length; ++i){
		var oldValue = arr[i];
		var newValue = transform(oldValue);
		newArray.push(newValue);
	}
	return newArray;
}

var newMappedArray = map([0, 1, 2], function(val){
	return val * 2;
});
console.log(newMappedArray);


// Example of performing map, then forEach
function transformer(name){
	return `${name} has ${name.length} letters`;
}
function thingDoer(value){
	console.log('You know what?', value);
}

// forEach(map(['Sharon', 'Aecio', 'Ken'], transformer), thingDoer);

// Native version
['Sharon', 'Aecio', 'Ken']
	.map(transformer)
	.forEach(thingDoer);

functions.js

// A bit about functions
// Functions in JavaScript are First Class Objects

// 1) Created at runtime. (see IIFE from scope.js)
// 2) Can be added to a data structure at runtime, such as a variable.
var x = 3;
console.log(x);
x = function(){
	console.log('Hi Ermis!');
};
console.log(x);
x();

// 3) Can be passed as parameters to a function
function doThisThing(fn){
	console.log('Do This Thing!');
	fn();
}
doThisThing(x);

// 4) Can be returned from a function
function returnAFunction(){
	console.log('I\'m returning a function!');
	return function(){
		console.log('Functions having functions!');
	}
}

// Top level function runs
var returnedFunction = returnAFunction();

debugger;
// Returned function runs
returnedFunction();

// This can be simplified to returnAFunction()();

scope.js

/*// The Adventures of Larryable the Variable

larryable = 'Hi, Im Larryable';
console.log(larryable);
console.log(global.larryable);

// Point out that, at the global scope, "larryable = 3" is the same as "var larryable = 3"
*/

/*function larryablesAdventure(){
	var larryable = 'Hi, Im Larryable!';
	console.log(larryable);
}

larryablesAdventure();
console.log(larryable);
// Now, larryable is not accessible from the outside scope.
*/
/*

// Now, let's look at nested scope, and a nested argument
function larryablesAdventure(){
	var larryable = 'Hi, Im Larryable!';
	function larrysBaby(){
		var maryable = 'Hi, Im Maryable!';
		console.log('Larryable', larryable);
		console.log('Maryable', maryable);
		console.trace();
	}
	larrysBaby();
	console.log(maryable);
}
larryablesAdventure();
*/

/*
Immediately
Invoked
Function
Expression
*/
(function(){
	for(var x = 0; x < 10; ++x){
		console.log(x);
	}
})();