Samples/JackTan_JavaScript_SampleCode2.html at master · jackziqitan/Samples · GitHub

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<!DOCTYPE html>
<html>
	<head lang="en">
		<meta charset="UTF-8">
		<title>Jack Tan JavaScript Sample Code 2</title>

		<script>
		/* Sample 1 */

			var foods = {
			  vegetable: 'carrot',
			  fruit: 'apple',
			  grain: 'corn'
			};

			// Print the key and values with console.log
			//    vegetable -> carrot
			//    fruit -> apple
			//    grain -> corn

			console.log("/----- Sample 1 -------/");
			// CODE HERE
			for (var key in foods) {
				console.log(key + " -> " + foods[key]);
			}

		/* Sample 2 */

			// Create a Car type as specified below

			// State variables
			// 		speed
			//    topSpeed

			// Methods
			// 		getSpeed() - Return the speed.
			// 		goFaster(amount) - Add to the speed variable. Resulting speed cannot exceed topSpeed.
			// 		slowDown(amount) - Subtract from the speed variable. Resulting speed cannot go below 0.


			// CODE HERE
			// Using ES6 class
			class Car {
				constructor(topSpeed) {
					this.speed = 0;
					if (topSpeed > 0)
						this.topSpeed = topSpeed;
					else {
						this.topSpeed = 0;
						console.log("Top speed should be greater than 0.");
					}
				}
				getSpeed() {
					return this.speed;
				}
				goFaster(amount) {
					this.speed += amount;
					this.speed = this.speed <= this.topSpeed ? this.speed : this.topSpeed;
					this.speed = this.speed >= 0 ? this.speed : 0; // In case the amount is negative
				}
				slowDown(amount) {
					this.speed -= amount;
					this.speed = this.speed <= this.topSpeed ? this.speed : this.topSpeed; // In case the amount is negative
					this.speed = this.speed >= 0 ? this.speed : 0;
				}
			}

			// Factory function. Create class by creating an object and returning it
			/*
			function Car(topSpeed) {
				var self = {};

				// Public field
				self.speed = 0;
				self.topSpeed;
				if (topSpeed > 0)
					self.topSpeed = topSpeed;
				else {
					self.topSpeed = 0;
					console.log("Top speed should be greater than 0.");
				}

				// Public method
				self.getSpeed = function() {
					return this.speed;
				};

				self.goFaster = function(amount) {
					this.speed += amount;
					this.speed = this.speed <= this.topSpeed ? this.speed : this.topSpeed;
					this.speed = this.speed >= 0 ? this.speed : 0; // In case the amount is negative
				};

				self.slowDown = function(amount) {
					this.speed -= amount;
					this.speed = this.speed <= this.topSpeed ? this.speed : this.topSpeed; // In case the amount is negative
					this.speed = this.speed >= 0 ? this.speed : 0;
				};

				return self;
			}
			*/

			// Using prototype
			/*
			function Car(topSpeed)
			{
				this.speed = 0;
				if (topSpeed > 0)
				{
					this.topSpeed = topSpeed;
				}
				else
				{
					this.topSpeed = 0;
					console.log("Top speed should be greater than 0.");
				}
			}
			Car.prototype.getSpeed = function()
			{
				return this.speed;
			}
			Car.prototype.goFaster = function(amount)
			{
				this.speed += amount;
				this.speed = this.speed <= this.topSpeed ? this.speed : this.topSpeed;
				this.speed = this.speed >= 0 ? this.speed : 0; // In case the amount is negative
			}
			Car.prototype.slowDown = function(amount)
			{
				this.speed -= amount;
				this.speed = this.speed <= this.topSpeed ? this.speed : this.topSpeed; // In case the amount is negative
				this.speed = this.speed >= 0 ? this.speed : 0;
			}
			*/

			console.log("/----- Sample 2 -------/");

			if(typeof Car !== 'undefined') {
				var c1 = new Car(25);
				c1.goFaster(10);
				c1.slowDown(5);
				console.log(c1.getSpeed()); // 5

				var c2 = new Car(25);
				c2.goFaster(25);
				c2.slowDown(1000);
				console.log(c2.getSpeed()); // 0

				console.log(c1.goFaster === c2.goFaster); // true if using class or prototype, false if using factory function

				var c3 = new Car(25);
				c3.goFaster(2500);
				console.log(c3.getSpeed()); // 25
			}

		/* Sample 3 */

			var x = {
			  name: "Jeff",

			  hello: function() {
				console.log("Hello, " + this.name);
			  }
			};

			var y = {
			  name: "Rafael"
			};

			// How can we call x.hello, but with "y" as the context so output will be "Rafael"

			console.log("/----- Sample 3 -------/");
			// CODE HERE
			// Can use call(), apply(), and bind()
			x.hello.call(y);
			//x.hello.apply(y);
			//x.hello.bind(y)();


		/* Sample 4 */

			console.log("/----- Sample 4 -------/");

			var a = ["one", "two", "three"];
			console.log(a.indexOf("two")); // output = 1

			a.indexOf = function(val) {
			  return 'HAHAHA';
			};

			console.log(a.indexOf("two")); // output = 'HAHAHA'

			// What are some ways to restore the functionality of indexOf?
			//

			// CODE HERE
			a.indexOf = Array.prototype.indexOf;
			//console.log(Array.prototype.indexOf.call(a, "two"));

			console.log(a.indexOf("two")); // output = 1

		/* Sample 5 */

			console.log("/----- Sample 5 -------/");

			function greet(name) {
			  return 'Hello, ' + name;
			}

			console.log(greet('Jeff')); // output = 'Hello, Jeff'

			// How can we redefine the greet function such that future calls add punctuation?
			//
			// CODE HERE
			greet = function(name) {
			  return 'Hello, ' + name + '!';
			}
			console.log(greet('Jeff')); // output = 'Hello, Jeff!'

		</script>
		</head>
	<body>
</html>