WordCamp Seattle 2017 JavaScript Workshop

JavaScript for WordPress Zac Gordon @zgordon https://javascriptforwp.com/wcsea

Go Here to Get Setup javascriptforwp.com/wcsea

Are We Ready?! 1. Slides and Example Files 2. Code
Editor (I'm using Atom) 3. JSONView Chrome Extension 4. Local WordPress Install (I'm using Local) 5. FakerPresser Plugin (For dummy content)

Workshop Overview 1. JavaScript [ JS 101, DOM, Events ]
2. The WordPress REST API [ Accessing, Arguments ] 3. JS & API in WP Themes [ Enqueuing, WP API ] 4. Homework! Checkout FREE 5 Days of JavaScript

JS 101 Pop Quiz!

Partner Up! 1 Point for Explaining with Words 1 Point
for Coding an Example

Question 1/8 What is a variable?

Question 2/8 What is an array?

Question 3/8 What is a function?

Question 4/8 What is an object?

Question 5/8 What is a loop?

Question 6/8 What is a conditional?

Question 7/8 How do you include JavaScript in HTML ?

Question 8/8 How do you include JavaScript in a WP
Theme?

JS 101

Variable A container for storing values (in memory) var username
= 'zgordon'; let username = 'zgordon'; const siteURL = 'https://site.com';

keyword var let const global scope YES NO NO function
scope YES YES YES block scope NO YES YES can be reassigned YES YES NO Checkout FREE 5 Days of JavaScript

Variable A container for storing values (in memory) var username
= 'zgordon', twitter = '@zgordon', website = 'zacgordon.com';

Array A collection of values var postIds = [ 1,
2, 3, 5 ]; var usernames = [ 'zgordon', 'admin' ];

Array A collection of values (zero indexed) var postIds =
[ 1, 2, 3, 5 ]; postIds[ 0 ] // Equals 1 postIds[ postIds.length - 1 ] // Last item

Functions Let us write, call and reuse blocks of code
function getPosts() { // Function Declaration var posts = apiMagic(); // Will learn.. return posts; } getPosts(); // Function Call getPosts // Function Reference

Function Parameters Can pass data into functions function getUser( id
= 0 ) { var user = apiMagic( id ); return user; } getUser( 1 );

Fat Arrow Functions Let us write, call and reuse blocks
of code var posts = getPosts( id => apiMagic( id ) ); Checkout FREE 5 Days of JavaScript

Objects Container with properties (values) and methods (functions). var post
= { title: 'Hello World!', render: function() { console.log( this.title ); } } post.title; post.render();

Loops Let us perform an action on a collection of
items. var postIds = [ 1, 7, 14, 34, 88, 117 ]; for ( let i = 0, max = postIds.length; i < max; i++ ) { console.log( 'Post #' + postIds[ i ] ); }

For Of Loop Lets us loop through an array var
postIds = [ 1, 7, 14 ]; for( let id of postIds ) { console.log( id ); }

For Each Method Lets us loop through an array var
postIds = [ 1, 7, 14 ]; postIds.forEach( id => { console.log( id ) } );

Mapping Mapping is a functional alternative to looping var postIds
= [ 1, 7, 14 ]; var newIds = postIds.map( id => { console.log( id ); });

Conditional Statements Tests to determine what code to run var
loggedIn = true; if ( true === loggedIn ) { console.log( 'Show dashboard' ); } else { console.log( 'Please login' ); }

Include JS in HTML <html> <head> </head> <body> <script> console.log(
'JS Running!' ); </script> </body> </html>

Include JS in HTML <html> <head> </head> <body> <script src="index.js"></script>
</body> </html>

Include JS in WP Theme function my_theme_scripts() { wp_enqueue_script( 'main-js',
get_template_directory_uri() . '/js/main.js', [ 'jquery', 'wp-api' ], time(), true ); } add_action( 'wp_enqueue_scripts', 'my_theme_scripts' );

The DOM The Document Object Model

The DOM is an API For HTML (XML & SVG)

BROWSER DOM HTML JavaScript

Build documents, navigate their structure, and add, modify, or delete
elements and content.

The DOM API Can • Select HTML elements from a
page • Navigate from one element to surrounding elements • Add, edit and delete HTML elements on a page • Build HTML elements and add to a page Checkout FREE 5 Days of JavaScript

Selecting & Setting HTML Elements

WordCamp Miami 2017 Selecting HTML Elements document.getElementById( 'main' ) document.getElementsByTagName(
'a' ) document.getElementsByClassName( 'post' )

WordCamp Miami 2017 Selecting HTML Elements document.querySelector( '.entry-title a' )
document.querySelectorAll( '.entry-title a' ) var h1El = document.querySelector( 'h1' ), aEl = h1El.querySelector( 'a' );

WordCamp Miami 2017 Selecting HTML Elements document.getElementById( 'main' ) document.getElementsByTagName(
'a' ) document.getElementsByClassName( 'post' ) document.querySelector( '.entry-title a' ) document.querySelectorAll( '.entry-title a' )

WordCamp Miami 2017 Getting Element Attributes el.innerText el.innerHTML el.id el.href
el.dataset.custom input.value var el = document.querySelector( 'a' ), input = document.querySelector( 'input' );

WordCamp Miami 2017 Setting Element Values var el = document.querySelector(
'a' ); el.href = 'https://javascriptforwp.com'; el.innerText = 'Link'; el.innerHTML = '<strong>Link</strong>'; input.value = 'zgordon';

WordCamp Miami 2017 Setting CSS Classes var el = document.querySelector(
'a' ); el.classList.add( 'post' ); el.classList.remove( 'post' ); el.classList.toggle( 'post' );

PRACTICE 1.1 Getting & Setting Nodes w JS

“Traversing” HTML Elements Checkout FREE 5 Days of JavaScript

WordCamp Miami 2017 Creating HTML & Adding it to a
Page

There Are No "HTML Elements” in the DOM

In the DOM Everything is a Node

Common Node Types • Document [9] • DocumentType [10] •
Element [1] • Text [3] • Comments [8] • DocumentFragments [11]

Common Node Types • Document [9] • DocumentType [10] •
Element [1] • Text [3] • Comments [8] • DocumentFragments [11] Checkout FREE 5 Days of JavaScript

10 Doctype Root / HTML 1 Body 1 Head 1
1 Title 3 Title Text 1 Header 1 Paragraph 3 Header Text 3 Text 1 Link 3 3 Link Text 9 Document Window

WordCamp Miami 2017 Creating Nodes document.createElement( 'p' ) document.createTextNode( 'Text'
)

WordCamp Miami 2017 Appending Nodes parent.appendChild( el ); parent.insertBefore( el,
elToGoBefore );

WordCamp Miami 2017 Appending Text to Element Nodes var p
= document.createElement( 'p' ), text = document.createTextNode( 'Text' ); p.appendChild( text );

WordCamp Miami 2017 Appending Nodes Example var pEl = document.querySelector(
'p' ), aEl = document.createElement( 'a' ), aText = document.createTextNode( 'Link' ); aEl.appendChild( aText ); aEl.href = 'https://javascriptforwp.com'; pEl.appendChild( aEl );

WordCamp Miami 2017 “Hacker Style” Appending Nodes var pEl =
document.querySelector( 'p' ), markup = ''; markup += '<a href="https://site.com">'; markup += 'Link Text'; markup += '</a>'; pEl.innerHTML = markup;

Practice 1.2 + 1.3  Creating & Appending Nodes

Events w JavaScript

WordCamp Miami 2017 Types of Events • Mouse events •
Keyboard events • Form events • Media events • Drag and Drop events • Window events • Many more…. Checkout FREE 5 Days of JavaScript

WordCamp Miami 2017 Hooking into Events w JavaScript 1. Inline
in HTML 2. Global 1 Off 3. Listeners Best <a onclick="alert('hi')">Alert</a> a.onclick = sayHi a.addEventListener( 'click', sayHi, false )

WordCamp Miami 2017 Event Listeners var linkEl = document.querySelector( 'a'
); linkEl.addEventListener( 'click', displayClickInfo ); function displayClickInfo() { alert( 'Link clicked!' ); }

WordCamp Miami 2017 The Event Object var linkEl = document.querySelector(
'a' ); linkEl.addEventListener( 'click', displayClickInfo ); function displayClickInfo( event ) { alert( event ); }

WordCamp Miami 2017 The Event Object link.addEventListener( 'click', showEvent );
function showEvent( event ) { console.log( event ); console.log( event.type ); console.log( event.target ); console.log( event.preventDefault() ); } Checkout FREE 5 Days of JavaScript

WordCamp Miami 2017 Removing Event Listeners var el = document.querySelector(
'a' ); el.addEventListener( 'click', sayHi ); el.removeEventListener( 'click', sayHi );

WordCamp Miami 2017 Removing Event Listeners var el = document.querySelector(
'a' ); el.addEventListener( 'click', sayHi ); el.remove(); // Listener still exists el = null; // Listener does NOT exist

Practice 1.4 Event Listeners Practice

2. The WordPress REST API [ Accessing, Arguments ] 3. JavaScript & WP API in Themes [ Enqueuing, jQuery, API ] 4. Homework!

The WordPress   REST API

The WP REST API Allows us to get, save, edit,
and remove content from WordPress using JSON & JavaScript.

The WP REST API Allows us to get, save, edit,
and remove content from WordPress using JavaScript.

The WordPress REST API /wp-json/wp/v2/posts /wp-json/wp/v2/revisions /wp-json/wp/v2/categories /wp-json/wp/v2/tags /wp-json/wp/v2/pages /wp-json/wp/v2/comments
/wp-json/wp/v2/taxonomies /wp-json/wp/v2/media /wp-json/wp/v2/users /wp-json/wp/v2/types /wp-json/wp/v2/statuses /wp-json/wp/v2/settings /wp-json/custom/v1/something /wp-json/another/v3/else

The WordPress REST API To access all of the posts
for your site: https://yoursite.com/wp-json/wp/v2/posts To access a post with an ID of “1” for your site: https://yoursite.com/wp-json/wp/v2/posts/1

The WordPress REST API To access all of the pages
for your site: https://yoursite.com/wp-json/wp/v2/pages To access a page with an ID of “5” for your site: https://yoursite.com/wp-json/wp/v2/pages/5

You can also customize what you get back.

The WordPress REST API https://yoursite.com/wp-json/wp/v2/posts ? per_page=10  &_embed  &search=hello%20world  &orderby=title 
&order=asc https://developer.wordpress.org/rest-api/reference/posts/#arguments

Practice 2.1  WP API in the Browser

WordPress API w AJAX + JS

AJAX Allows us to get content from a server or
send content to a server using JavaScript.

AJAX w WP API Allows us to get, save, edit
and delete WordPress content using JavaScript and JSON.

Ways to Make JS AJAX Calls • XMLHttpRequests() [Web API]
• fetch() [Web API] • jQuery [Library] • Axios [Library] • WP API Specific [In Core, Decoupled] Checkout FREE 5 Days of JavaScript

WP API AJAX Behind the Scenes 1. Define the URL
to use 2. Make a request to the URL 3. Get JSON back from 4. Parse JSON into Native JavaScript 5. Use Native JavaScript

Pseudo AJAX var postsJSON = fetch('https://wp.dev/wp-json/wp/v2/posts'), posts = JSON.parse( postsJSON
); for( let post of posts ) { renderPost( post ); }

AJAX with jQuery $.ajax({ type: 'get', url: 'https://site.com/wp-json/wp/v2/posts/', data: {
per_page: 3, order: 'asc' }, success: function( response ) { for( let post of response ) { renderPost( post ); } } });

Practice 2.2 + 2.3  WP API with Ajax

JS + API Inside of WP

Enqueuing JavaScript The process of loading JavaScript into a theme
or the admin area via PHP functions. wp_enqueue_script() wp_localize_script()

function my_theme_scripts() { wp_enqueue_script( 'main-js', // Unique name get_template_directory_uri() .
'/js/main.js', // Path [ 'jquery', 'wp-api' ], // Dependencies time(), // Version true ); // Include in footer (v header) } add_action('wp_enqueue_scripts', 'my_theme_scripts', 999); wp_enqueue_script()

function my_theme_scripts() { wp_enqueue_script( 'main-js', ... ); wp_localize_script( 'main-js', //
File to localize 'myGlobalVars', // Name of localize object [ // Array of properties 'siteUrl' => esc_url( home_url() ), 'siteName'=> get_bloginfo( 'name' ) ] ); } add_action('wp_enqueue_scripts', 'my_theme_scripts', 999); wp_localize_script()

functions.php function my_theme_scripts() { wp_enqueue_script( 'main-js', ... ); wp_localize_script( 'main-js',
'myGlobalVars', ... ); } add_action('wp_enqueue_scripts', 'my_theme_scripts', 999); main.js console.log( myGlobalVars.siteUrl ); wp_localize_script()

Practice 3.1  Enqueuing JavaScript in a Theme

jQuery + WordPress

WordPress comes with Several JS Libraries Available to Us

function my_theme_scripts() { wp_enqueue_script( 'main-js', // Unique name get_template_directory_uri() .
'/js/main.js', // Path [ 'jquery' ], // Dependencies time(), // Version true ); // Include in footer (v header) } add_action('wp_enqueue_scripts', 'my_theme_scripts', 999); jQuery Dependency

The $ in jQuery is NOT available by default

jQuery( '.this-works' ).show();

(function( $ ) { $('.this-works').show(); })( jQuery ); Immediately Evoked
Function Expression (IEFE)

Practice 3.2  Using jQuery for AJAX

WordCamp Miami 2017 Learn JavaScript More Deeply with Me! javascriptforwp.com/wcsea

WordCamp Seattle 2017 JavaScript Workshop

WordCamp Seattle 2017 JavaScript Workshop

More Decks by Zac Gordon

Other Decks in Education

Featured

Transcript