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Introduction to React.js
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Radoslav Stankov
September 22, 2015
Technology
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Introduction to React.js
My talk for Sofia Wordpress Meetup
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Transcript
Introduction to React.js Radoslav Stankov 22/09/2015
Radoslav Stankov @rstankov http://rstankov.com http://blog.rstankov.com http://github.com/rstankov
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<div className="post-list"> <article className="post-item"> <button className="vote-button">{post.votesCount}</button> <div> <h1>{post.name}</h1> <p>{post.headline}</p> </div>
<button className="comment-button">{post.commentsCount}</button> </article> <article className="post-item"> <button className="vote-button">{post.votesCount}</button> <div> <h1>{post.name}</h1> <p>{post.headline}</p> </div> <button className="comment-button">{post.commentsCount}</button> </article> <!—- more posts —-> </div>
var PostList = React.createClass({ render: function() { } });
var PostList = React.createClass({ render: function() { } }); ?
Render
component.render() props, state
Virtual DOM
Virtual Dom React Element React Element React Element React Element
React Element
Virtual Dom DOM Element DOM Element DOM Element DOM Element
DOM Element
Virtual Dom React Element React Element React Element React Element
React Element
Virtual Dom React Element React Element React Element React Element
React Element
Virtual Dom React Element React Element React Element React Element
React Element
Virtual Dom React Element React Element React Element React Element
React Element React Element React Element React Element React Element React Element
Virtual Dom React Element React Element React Element React Element
React Element React Element React Element React Element React Element React Element DOM Element DOM Element DOM Element DOM Element DOM Element
Virtual Dom React Element React Element React Element React Element
React Element React Element React Element React Element React Element React Element DOM Element DOM Element DOM Element DOM Element DOM Element DOM Element DOM Element DOM Element DOM Element DOM Element
var PostList = React.createClass({ render: function() { } });
var PostList = React.createClass({ render: function() { var posts =
this.props.posts.map(function(post) { return ( React.createElement("article", {className: "post-item"}, React.createElement("button", {className: "vote-button"}, post.vo React.createElement("div", null, React.createElement("h1", null, post.name), React.createElement("p", null, post.headline) ), React.createElement("button", {className: "comment-button"}, post ) ); }); return ( React.createElement("div", {className: "post-list"}, posts) ) } });
Can’t tell if it is true or just trolling
var PostList = React.createClass({ render: function() { var posts =
this.props.posts.map(function(post) { return ( <article className="post-item"> <button className="vote-button">{post.votesCount}</button> <div> <h1>{post.name}</h1> <p>{post.headline}</p> </div> <button className="comment-button">{post.commentsCount}</button> </article> ); }); return ( <div className="post-list"> {posts} </div> ) } });
STILL can’t tell if it is true or just trolling
JSX <article className="post-item"> <VoteButton /> <div> <h1>{post.name}</h1> <p>{post.headline}</p> </div> <CommentButton
/> </article>
React.createElement("button", {className: "vote-button"}, post.votesCount)) <button className="vote-button">{post.votesCount}</button>
React.createElement("div", null, React.createElement("h1", null, post.name), React.createElement("p", null, post.headline) ) <div>
<h1>{post.name}</h1> <p>{post.headline}</p> </div>
Code vs Template
render() { return this.props.results.map(function(result) { return ( <article> <h1>{result.name}</h1> <p>{result.headline}</p>
<a href={result.link}>visit</a> </article> ); }); } Looping
<div ng-repeat="result in results track by result.id"> <article> <h1>{{result.name}}</h1> <p>{{result.headline}}</p>
<a ng-href="{{result.link}}">visit</a> </article> </div> Looping
{{#each result in results}} <article> <h1>{{result.name}}</h1> <p>{{result.headline}}</p> {{#link-to result.link}}visit{{/link-to}} </article>
{{/each}} Looping
render() { if (this.props.results.length === 0) { return ( <strong>No
results found</strong> ); } return this.props.results.map(function(result) { return ( <article> <h1>{result.name}</h1> <p>{result.headline}</p> <a href={result.link}>visit</a> </article> ); }); } Conditions
<div ng-switch="results.length"> <div ng-switch-when="0"> <strong>No results found</strong> </div> <div ng-switch-default>
<div ng-repeat="result in results track by result.id"> <article> <h1>{{result.name}}</h1> <p>{{result.headline}}</p> <a ng-href="{{result.link}}">visit</a> </article> </div> </div> </div> Conditions
{{#if results}} {{#each result in results}} <article> <h1>{{result.name}}</h1> <p>{{result.headline}}</p> {{#link-to
result.link}}visit{{/link-to}} </article> {{/each}} {{else}} <strong>No results found</strong> {{/if}} Conditions
render() { if (this.props.results.length === 0) { return this.renderEmptyMessage(); }
return this.renderResultsList(); } Components
render() { if (this.props.results.length === 0) { return <EmptyMessage />
} return <ResultsList results={this.props.results} /> } Components
<div ng-switch="results.length"> <div ng-switch-when="0"> <my-app-no-results /> </div> <div ng-switch-default> <my-app-results-list
/> </div> </div> Components
<div ng-switch="results.length"> <div ng-switch-when="0"> <ng-include name="no-results.html" /> </div> <div ng-switch-default>
<ng-include name="results-list.html" /> </div> </div> Components
{{#if results}} {{my-app-no-results}} {{else}} {{my-app-no-results-list}} {{/if}} Components
{{#if results}} {{partial "no-results"}} {{else}} {{partial "results-list"}} {{/if}} Components
{{#if results}} {{view "no-results"}} {{else}} {{view "results-list"}} {{/if}} Components
var PostList = React.createClass({ render: function() { var posts =
this.props.posts.map(function(post) { return ( <article className="post-item"> <button className="vote-button">{post.votesCount}</button> <div> <h1>{post.name}</h1> <p>{post.headline}</p> </div> <button className="comment-button">{post.commentsCount}</button> </article> ); }); return ( <div className="post-list"> {posts} </div> ) } });
None
None
var PostList = React.createClass({ render: function() { var posts =
this.props.posts.map(function(post) { return <PostItem key={post.id} post={post} />; }); return ( <div className="post-list"> {posts} </div> ) } });
var PostItem = React.createClass({ render: function() { return ( <article
className="post-item"> <button className="vote-button">{this.props.post.votesCount}</button> <div> <h1>{this.props.post.name}</h1> <p>{this.props.post.headline}</p> </div> <button className="comment-button">{this.props.post.commentsCount}</button> </article> ); } });
var PostItem = React.createClass({ render: function() { var className =
classNames('vote-button', {active: this.props.post.hasVoted}); return ( <article className="post-item"> <button className={className}>{this.props.post.votesCount}</button> <div> <h1>{this.props.post.name}</h1> <p>{this.props.post.headline}</p> </div> <button className="comment-button">{this.props.post.commentsCount}</button> </article> ); } });
var PostItem = React.createClass({ getInitialState: function() { return { hasVoted:
this.props.post.hasVoted, votesCount: this.props.post.votesCount, }; }, render: function() { var className = classNames('vote-button', {active: this.state.hasVoted}); return ( <article className="post-item"> <button className={className} onClick={this.handleVoteClick}>{this.state.votesCount}</button> <div> <h1>{this.props.post.name}</h1> <p>{this.props.post.headline}</p> </div> <button className="comment-button">{this.props.post.commentsCount}</button> </article> ); }, handleVoteClick: function () { var updatedPost = toggleVote(this.props.post); this.setState({ hasVoted: updatedPost.hasVoted, votesCount: updatedPost.votesCount, }); } });
Virtual Dom div article article button div button h1 p
Virtual Dom PostList PostItem PostItem button div button h1 p
Virtual Dom PostList PostItem PostItem button div button h1 p
Virtual Dom PostList PostItem PostItem button div button h1 p
Virtual Dom PostList PostItem PostItem Vote Button div h1 p
button
Virtual Dom PostList PostItem PostItem Vote Button div h1 p
button
var PostItem = React.createClass({ render: function() { return ( <article
className="post-item"> <VoteButton post={this.props.post} /> <div> <h1>{this.props.post.name}</h1> <p>{this.props.post.headline}</p> </div> <button className="comment-button">{this.props.post.commentsCount}</button> </article> ); } });
@rstankov Thanks :)