fm-learn-es2015/index.html at master · fostermadeco/fm-learn-es2015 · GitHub

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<!doctype html>
<html>
	<head>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">

		<title>ES2015+</title>

		<link rel="stylesheet" href="css/reset.css">
		<link rel="stylesheet" href="css/reveal.css">
		<link rel="stylesheet" href="css/theme/solarized.css">

		<!-- Theme used for syntax highlighting of code -->
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			var link = document.createElement( 'link' );
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		</script>
	</head>
	<body>
		<div class="reveal">
			<div class="slides">
				<section>
					<h1>Intro to Javascript ES2015+</h1>
				</section>

				<section>
					<h2>Goals</h2>
					<p>💥 Introduce you to a useful subset of features</p>
					<p>💥 Ease you into some new syntax</p>
				</section>

				<section>
					<h2>FM Javascript Quick Reference ES2015+</h2>
					<small>https://github.com/fostermadeco/standards/</small>
				</section>

				<section>
					<h2>JS Versions</h2>
					<p>ECMAScript is the scripting language that forms the basis of JavaScript.</p>
					<p>When you see ES6, it means that that version of JavaScript is following the specifications in the sixth edition of ECMAScript</p>
				</section>

				<section>
					<h2>A version is a set of features</h2>
					<p>💥 ES6 === ES2015</p>
					<p>💥 Going forward, ECMAScript will be updated annually</p>
					<p>💥 ES2015, ES2017, ES2018, ESNext</p>
				</section>

				<section>
					<h2>Compiling: Babel</h2>
					<p>Converts ES2015+ code into backwards compatibility js that can be read by current and older browsers</p>
					<p>💥 Syntax</p>
					<p>💥 Polyfills for built-ins</p>
				</section>

				<section data-markdown><textarea data-template>
						## Syntax vs. Built-ins

						Syntax: `let` & `const`, arrow functions, `class`

						```javascript
						const cat = 'Sylvie';
						// Babel compiles to
						var cat = 'Sylvie';
						```

						Built-ins (methods and objects):

						```javascript
						const cats = ['Sylvie', 'Blixa', 'Max', 'Ramona'];

						// String.prototype.startsWith - ES2015
						cats[0].startsWith('Sy'); // true

						// Array.prototype.find - ES2015
						cats.find(cat => cat === 'Sylvie'); // Sylvie

						// Array.prototype.includes - ES2016
						cats.includes('Sylvie'); // true
						```
					</textarea></section>

				<section>
					<h2>Mix</h2>
					<small>Wrapper around Webpack (uses Babel)</small>
					<p>With our Mix setup you can safely use ES2015 and ES2017</p>
					<small>💥 Mix uses Babel to compile ES2015+ syntax to vanilla JS.</small>
					<small>💥 Our Mix setup also adds polyfills to support <em>used</em> ES2015+ built-ins for older browsers like IE11.</small>
				</section>


				<section data-markdown><textarea data-template>
					<h2>Eslint & Prettier</h2>
					<a href="https://github.com/fostermadeco/eslint-config-fostermade">
						<img src="http://kellypackercom.s3.amazonaws.com/pages/eslint-prettier.png" />
					</a>
				</textarea></section>

				<section data-markdown><textarea data-template>
					## Misc notes

					Strict mode included

					```javascript
					"use strict";
					```

					Unnecessary if file is included before closing body tag
					```javascript
					$(document).ready({});
					```
				</textarea></section>

				<section data-markdown><textarea data-template>
					<h2>ES2015+ Features</h2>
				</textarea></section>

				<section data-markdown><textarea data-template>
					## Variable Declarations

					<small>ES2015 introduced two new ways to declare</small>

					<p>var</p>
					<p>let</p>
					<p>const</p>
				</textarea></section>

				<section data-markdown><textarea data-template>
					## `var`

					not block scoped

					```javascript
					var x = 1;

					if (x === 1) {
						var x = 2;

						console.log(x);
						// expected output: 2
					}

					console.log(x);
					// expected output: 2
					```

					**When to use:**

					<small>You don't need to change old code, but I wouldn't suggest using `var` on new code.</small>
				</textarea></section>
				<section data-markdown><textarea data-template>
					## `let`

					1) block scope variable 2) value can change

					```javascript
					let x = 1;
					x = 2;

					if (x === 1) {
						let x = 3;

						console.log(x);
						// expected output: 3
					}

					console.log(x);
					// expected output:2
					```
					**When to use**

					<small>When the variable will be reassigned a new value.</small>

				</textarea></section>
				<section data-markdown><textarea data-template>
					## `const`

					block scope variable that can't change

					```javascript
					const number = 42;

					try {
						number = 99;
					} catch(err) {
						console.log(err);
						// expected output: TypeError: invalid assignment to const `number'
						// Note - error messages will vary depending on browser
					}

					console.log(number);
					// expected output: 42
					```
				</textarea></section>

				<section data-markdown><textarea data-template>
					## Template Literals

					```javascript
					const first = 'Kelly';
					const last = 'Packer';

					// old
					const intro = 'My name is ' + first + ' ' + last + '!';

					// template literal
					const intro2 = `My name is ${first} ${last}!`;

					// multi-line template literal
					const headerTemplate = `
						<div>
							<h1>Hi, my name is ${first} ${last}!</h1>
						</div>
					`;
					```
				</textarea></section>
				<section data-markdown><textarea data-template>
					## Iterables/Loops

					`for`

					Old, difficult syntax 🛑:
					```javascript
					const names = ['Sylvie', 'Max', 'Blixa', 'Ramona'];

					for (let i = 0; i < names.length; ++i) {
						const name = names[i];
					}
					```
				</textarea></section>
				<section data-markdown><textarea data-template>
					`forEach()`

					<small>💥 For arrays. 😢 Can't break out of it.</small>

					```javascript
					const names = ['Sylvie', 'Max', 'Blixa', 'Ramona'];

					names.forEach(function(name, index) {
						console.log(name, index);
					});
					```
				</textarea></section>
				<section data-markdown><textarea data-template>
					`for/in`

					<small>For objects, but can be used with arrays (as long as order isn't important).</small>

					```javascript
					const cat = {name: 'Sylvie', type: 'calico', gender: 'female'};

					for (const key in cat) {
						const value = cat[key];
						// name Sylvie
						console.log(key, value);
					}
					```
				</textarea></section>
				<section data-markdown><textarea data-template>
					`for/of`

					<p>💥 Very versatile.</p>
					<p>💥 Can be used on anything iterable: array, string, object (ES2017), dom collection (node list), arguments, string, map or set.</p>
				</textarea></section>

				<section data-markdown><textarea data-template>
					`for/of`

					<small>With an array:</small>
					```javascript
					const names = ['Sylvie', 'Max', 'Blixa', 'Ramona'];

					for (const [index, item] of names.entries()) {
						// 0 Sylvie
						console.log(index, item);
					}
					```

					<small>💥 `array.entries` returns a new Array iterator object</small>

					<small>💥 Uses destructuring</small>
				</textarea></section>

				<section data-markdown><textarea data-template>
					`for/of`

					<small>With an object:</small>
					```javascript
					const cat = { name: 'Sylvie', type: 'calico', gender: 'female' };

					for (const [key, value] of Object.entries(cat)) {
						// name Sylvie
						console.log(key, value);
					}
					```

					<small>💥 `Object.entries(obj)` returns array of [key, value]</small>

					<small>💥 Uses destructuring</small>
				</textarea></section>

				<section data-markdown>
					<textarea data-template>
						## Object and Array Destructuring

						Say you have an object that you want to use some properties from.
						```javascript
						const person = {
							firstName: 'Adam',
							lastName: 'Tsai',
							jobTitle: 'Web developer',
						};
						```

						You might write something like this.

						```javascript
						const message = `Hello, ${person.firstName} ${person.lastName}.`;
						```

						Or you might write it like this.
						```javascript
						const firstName = person.firstName;
						const lastName = person.lastName;

						const message = `Hello, ${firstName} ${lastName}.`;
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						#### Object and Array Destructuring

						With destructuring
						```javascript
						const { firstName, lastName } = person;
						const message = `Hello, ${firstName} ${lastName}.`;
						```

						Works with arrays too
						```javascript
						const people = [
							'Jon Snow',
							'Daenerys Targaryen',
							'Tyrion Lannister'
						];

						const [ jon, dany, tyrion ] = people;
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						#### Object and Array Destructuring

						You can also alias your variables
						```javascript
						const { firstName: first, lastName: last } = person;
						const message = `Hello, ${first} ${last}.`;
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						## Arrow Functions
						(AKA "fat arrow" syntax)

						A more concise syntax for writing function expressions.

						Pre-ES2015 Function Expression
						```javascript
						var addTwoNumbers = function (a, b) {
							return a + b;
						}
						```

						ES2015
						```javascript
						const addTwoNumbers = (a, b) => {
							return a + b;
						}
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						#### Arrow Functions

						If your function is just a single expression, then this can also be writen with an implicit return
						```javascript
						const addTwoNumbers = (a, b) => (
							a + b
						);
						```

						or just
						```javascript
						const addTwoNumbers = (a, b) => a + b;
						```

						If your function has just a single parameter, you can omit the parentheses:
						```javascript
						const multiplyBy5 = a => a * 5;
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						#### Arrow Functions

						Not meant to 100% replace `function`. The fat arrow changes the way `this` is bound.

						```javascript
						$('input[name="first_name"]').on('change', function () {
							var inputValue = $(this).val();
							alert(inputValue);
						});

						$('input[name="first_name"]').on('change', () => {
							var inputValue = $(this).val(); // This will result in an error
							alert(inputValue);
						});
						```

					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						## Default Function Parameters

						Old
						```javascript
						function addTwoNumbers(a, b) {
							if (typeof b === 'undefined') {
								b = 0;
							}

							return a + b;
						}

						addTwoNumbers(5);
						```

						New
						```javascript
						function addTwoNumbers(a, b = 0) {
							return a + b;
						}

						addTwoNumbers(5);
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						## Object Literal property value shorthand

						<small>If you are assigning to an object property from a variable of the same name, you can use this shorthand.</small>

						```javascript
						const goat = 1;
						const pig = 2;
						const bear = 3;
						// OLD
						const combined = { goat: goat, pig: pig, bear: bear };
						// NEW
						const combined = { goat, pig, bear };
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						<h2>Fin</h2>

						<h4>Questions?</h4>
						<small><a href="https://kangax.github.io/compat-table/es2016plus/">ECMAScript compatibility table</a></s>
					</textarea>
				</section>

				<section data-markdown><textarea data-template>
						## Extra Credit

						New String & Array methods

						```javascript
						const cats = ['Sylvie', 'Blixa', 'Max', 'Ramona'];

						// String.prototype.startsWith - ES2015
						cats[0].startsWith('Sy'); // true
						// .endsWith, .includes

						// Array.prototype.find - ES2015
						cats.find(cat => cat === 'Sylvie'); // Sylvie

						// Array.prototype.includes - ES2016
						cats.includes('Sylvie'); // true

						Array.prototype.filter
						Array.prototype.map
						Array.prototype.some
						Array.prototype.every
						```
					</textarea></section>

				<!--
				<section data-markdown>
					<textarea data-template>
						## Spread Operator

						Official definition on MDN docs:

						Spread syntax allows an iterable such as an array expression or string to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected, or an object expression to be expanded in places where zero or more key-value pairs (for object literals) are expected.

						???
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						#### Spread Operator - Arrays

						Concatenating (Old)
						```
						const cats = ['Mittens', 'Bootsy, 'Miss Cinderella'];
						const dogs = ['Rover', 'Bud', 'Gromit'];
						const chaos = cats.concat(dogs);
						```

						Concatenating (New)
						```
						const cats = ['Mittens', 'Bootsy, 'Miss Cinderella'];
						const dogs = ['Rover', 'Bud', 'Gromit'];
						const chaos = [...cats, ...dogs];
						```

						Cloning:
						```
						const cats = ['Mittens', 'Bootsy, 'Miss Cinderella'];
						const copyOfCats = [...cats];
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						#### Spread Operator - Objects

						Merging (Old)
						```
						const girlfriendsCat = {
							name: 'Zy',
							fat: true,
							lazy: true,
							limbs: 'natural'
						};

						const bionicLegs = { limbs: 'bionic' };
						const upgradedCat = Object.assign({}, girlfriendsCat, bionicLegs);
						console.log(upgradedCat) // { name: 'Zy' fat: true, lazy: true, limbs: 'bionic' }

						```

						Merging (New)
						```
						const girlfriendsCat = {
							name: 'Zy',
							fat: true,
							lazy: true,
							limbs: 'natural'
						};

						const bionicLegs = { limbs: 'bionic' };
						const upgradedCat = { ...girlfriendsCat, ...bionicLegs };
						console.log(upgradedCat) // { name: 'Zy' fat: true, lazy: true, limbs: 'bionic' }
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						#### Spread Operator - Function calls

						```
							const someNumbers = [9, 4, 7, 1];
							const min = Math.min(...someNumbers);
							console.log(min); // 1
						```
					</textarea>
				</section>

				<section data-markdown>
					<textarea data-template>
						## Rest Operator

						The rest parameter syntax allows us to represent an indefinite number of arguments as an array.

						```
						function sumAll(...numbers) { // args is the name for the array
							let sum = 0;
							numbers.forEach(number => (sum += number));
							return sum;
						}

						console.log(sumAll(1)); // 1
						console.log(sumAll(1, 2)); // 3
						console.log(sumAll(1, 2, 3)); // 6
						```
					</textarea>
				</section>
				-->
			</div>
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