Develop Reference

Display array element ReactJS

UPD: How can I display elment of the array in my component (WeatherCityName - h2)? It can be seen that the array is loaded, but when I point out the property - an error occurs, it may be a problem in the syntax?
var WeatherBox = React.createClass({
handleWeatherSubmit: function(text) {
$.ajax({
url: this.props.url,
dataType: 'json',
type: 'POST',
data: 'cityName=' + text,
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
getInitialState: function() {
return {data: []};
},
render: function() {
return (
<div className="wetherBox">
<h1> Weather</h1>
<WeatherForm onWeatherSubmit={this.handleWeatherSubmit} />
<WeatherCityName data={this.state.data[0]} />
<WeatherList data={this.state.data} />
</div>
);
}
});
var WeatherCityName = React.createClass({
render: function(){
return(
<h2>{this.state.data[0].cityName}</h2>
);
}
});

Sure, just put <h2>{weatherItem.cityName}</h2> directly in the <div>.
var WeatherList = React.createClass({
render: function() {
var weatherNodes = this.props.data.map(function(weatherItem) {
return (
<div className="city-item-with-title">
<h2>{weatherItem.cityName}</h2>
<WeatherItem
cityid={weatherItem.cityid}
type={weatherItem.type}
src={weatherItem.src}
temp={weatherItem.temp}
tempFrom={weatherItem.tempFrom}
tempTo={weatherItem.tempTo}
key={weatherItem.id}
/>
</div>
);
});
return (
<div className="weatherList">
{weatherNodes}
</div>
);
}
});
Edit: I'm not sure which weather item you want to use as a title, perhaps this.props.data[0]?
Edit 2: Just assumed you want to use the first weather item.
Edit 3: One title for each weatherItem, grouped inside a div together with the corresponding weatherItem.

React Tutorial and Sinatra API: Uncaught TypeError: this.props.data.map is not a function

I know, there are hundreds of questions with the same title, but nothing helped my get a solution for my problem. so I worked through the official react js tutorial and build a small API with sinatra to test things.
so everything works really good. except of one error I see in the console when submitting a new "Joke" (called them jokes instead of comments ;)) via AJAX.
app.js:66 Uncaught TypeError: this.props.data.map is not a function
This happens when I click on submit. I logged the state when submitting the form and everything seems to be okay (array with the temporary objects).
so the new Joke is being added and written to the database. It works but i don't know why I'm getting the Uncaught TypeError in the console.
thanks in advance!
var JokeBox = React.createClass({
loadJokesFromServer: function() {
$.ajax({
url: this.props.url,
dataType: 'json',
cache: false,
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
handleJokeSubmit: function(joke) {
var jokes = this.state.data;
var tmpJoke = jQuery.extend({}, joke)
tmpJoke.id = new Date();
tmpJoke.likes = 0;
jokes.unshift(tmpJoke);
this.setState({data: jokes}, function(){
$.ajax({
url: this.props.url,
dataType: 'json',
type: 'POST',
data: joke,
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
this.setState({data: jokes});
console.error(this.props.url, status, err.toString());
}.bind(this)
});
});
},
getInitialState: function() {
return {data: []};
},
componentDidMount: function() {
this.loadJokesFromServer();
setInterval(this.loadJokesFromServer, this.props.pollInterval);
},
render: function() {
return (
<div className="jokes">
<h1>Jokes</h1>
<JokeForm onJokeSubmit={this.handleJokeSubmit} />
<JokeList data={this.state.data} />
</div>
);
}
});
var JokeList = React.createClass({
render: function() {
var jokeNodes = this.props.data.map(function(joke) {
return (
<Joke content={joke.content} key={joke.id} likes={joke.likes} />
);
});
return (
<div className="jokeList">
{jokeNodes}
</div>
);
}
});
var JokeForm = React.createClass({
getInitialState: function() {
return {content: ''};
},
handleContentChange: function(e) {
this.setState({content: e.target.value});
},
handleSubmit: function(e) {
e.preventDefault();
var content = this.state.content.trim();
if (!content) {
return;
}
this.props.onJokeSubmit({content: content});
this.setState({content: ''});
},
render: function() {
return (
<form className="jokesForm" onSubmit={this.handleSubmit}>
<input
type="text"
placeholder="Your Joke!"
value={this.state.content}
onChange={this.handleContentChange}
/>
<input type="submit" value="Send joke" />
</form>
);
}
});
var Joke = React.createClass({
render: function() {
return (
<div className="joke">
<p className="jokeContent">{this.props.content}</p>
<p className="jokeLikes">{this.props.likes}</p>
</div>
);
}
});
ReactDOM.render(
<JokeBox url="/api/jokes" pollInterval={2000} />,
document.getElementById('app')
);
// EDIT
So I played around with the sample tutorial repo from the tutorial. I log the data in the handleSubmit in the success function right before the state is set. And I figured out: my data is ja object of the actual new Joke, in the sample tutorial it is an array of all comments. How could this be? I can't find my mistake...

try
handleJokeSubmit: function(joke) {
let {data}= this.state;
$.post(this.props.url, joke, res=>{
this.setState({data:[res,...data]});
})
.fail( err=>alert('Error: ' + err.responseText));
}
///EDIT es5
handleJokeSubmit: function(joke) {
var data = this.state.data;
$.post(this.props.url, joke, function(res){
this.setState({data:[res].concat(data)});
}.bind(this))
.fail( function(err){alert('Error: ' + err.responseText)});
}

react.js call parent function from child

I know there are a few similar questions here and here but I am having a tough time understanding what is the correct thinking today on this and extrapolating it to my situation.
I have a simple app, ScoreBox has a ScoreList which has many Scores. I want to have a Score onClick call ScoreList handleScoreRemove. I am showing the full js file, but the most important lines are line 5 and line 77.
var Score = React.createClass({
removeRecord: function(e){
// How do I do this?
ScoreList.handleScoreRemove(e);
},
render: function() {
var team1_style = (this.props.team1_score >= this.props.team2_score) ?
{fontWeight: 'bold'} : {};
var team2_style = (this.props.team2_score >= this.props.team1_score) ?
{fontWeight: 'bold'} : {};
return (
<tr>
<td style={team1_style}>{this.props.team1_name}:</td><td style={team1_style}>{this.props.team1_score}</td>
<td style={team2_style}>{this.props.team2_name}:</td><td style={team2_style}>{this.props.team2_score}</td>
<td><a hef="#" id={this.props.id} onClick={this.removeRecord}>remove</a></td>
</tr>
);
}
});
var ScoreBox = React.createClass({
loadScoresFromServer: function() {
$.ajax({
url: this.props.url,
dataType: 'json',
cache: false,
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
handleScoreSubmit: function(score) {
var scores = this.state.data;
// Optimistically set an id on the new score. It will be replaced by an
// id generated by the server. In a production application you would likely
// not use Date.now() for this and would have a more robust system in place.
score.id = Date.now();
var newScores = scores.concat([score]);
this.setState({data: newScores});
$.ajax({
url: this.props.url,
dataType: 'json',
type: 'POST',
data: score,
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
this.setState({data: scores});
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
getInitialState: function() {
return {data: []};
},
componentDidMount: function() {
this.loadScoresFromServer();
setInterval(this.loadScoresFromServer, this.props.pollInterval);
},
render: function() {
return (
<div className="scoreBox">
<h1>Scores</h1>
<ScoreList data={this.state.data} />
<ScoreForm onScoreSubmit={this.handleScoreSubmit} />
</div>
);
}
});
var ScoreList = React.createClass({
handleScoreRemove: function(score) {
var scores = this.state.data;
var index_of_score = array.indexOf(score);
var newScores = scores.splice(index_of_score, 1);
this.setState({data: newScores});
$.ajax({
url: this.props.url + "/" + score[id],
dataType: 'json',
type: 'DELETE',
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
this.setState({data: scores});
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
render: function() {
var scoreNodes = this.props.data.map(function(score) {
return (
<Score key={score.id} id={score.id} team1_name={score.team1_name} team1_score={score.team1_score} team2_name={score.team2_name} team2_score={score.team2_score} >
</Score>
);
});
return (
<div className="scoreList">
<table>
<tbody>
{scoreNodes}
</tbody>
</table>
</div>
);
}
});
var ScoreForm = React.createClass({
checkForCompleteForm: function(){
if (this.state.team1_name.length > 0 && this.state.team2_name.length > 0 && this.state.team1_score.length > 0 && this.state.team2_score.length > 0)
{
// enable the button
$("input[type=submit]").removeAttr('disabled');
}
},
getInitialState: function() {
return {id: '', team1_name: '', team1_score: '', team2_name: '', team2_score: ''};
},
handleChange : function (e) {
// this is a generic handle change function that uses the html id to set the state instead of
// having a bunch of if statements
var stateObject = function() {
var returnObj = {};
returnObj[this.target.id] = this.target.value;
return returnObj;
}.bind(e)();
// setState is async which makes this painful
// JCN - why when I pass checkForCompleteForm as 2nd param it doesnt work, but instead I need this
// function bind stuff... need to understand exactly what this is doing
this.setState( stateObject, function(){
this.checkForCompleteForm();
}.bind(this));
},
handleSubmit: function(e) {
e.preventDefault();
var team1_name = this.state.team1_name.trim();
var team1_score = this.state.team1_score.trim();
var team2_name = this.state.team2_name.trim();
var team2_score = this.state.team2_score.trim();
if (!team1_name || !team1_score ) {
return;
}
this.props.onScoreSubmit({team1_name: team1_name, team1_score: team1_score,team2_name: team2_name, team2_score: team2_score });
this.setState({team1_name: '', team1_score: '', team2_name: '', team2_score: ''});
},
render: function() {
return (
<form className="scoreForm" onSubmit={this.handleSubmit}>
<input
id='team1_name'
type="text"
placeholder="Team1 Name"
value={this.state.team1_name}
onChange={this.handleChange}
/>
<input
id='team1_score'
type="number"
placeholder="Team1 Score"
value={this.state.team1_score}
onChange={this.handleChange}
/>
<input
id='team2_name'
type="text"
placeholder="Team2 Name"
value={this.state.team2_name}
onChange={this.handleChange}
/>
<input
id='team2_score'
type="number"
placeholder="Team2 Score"
value={this.state.team2_score}
onChange={this.handleChange}
/>
<input type="submit" value="Post" disabled />
</form>
);
}
});
ReactDOM.render(
<ScoreBox url="/api/scores" pollInterval={2000} />,
document.getElementById('content')
);

You need to pass handleScoreRemove through props
var scoreNodes = this.props.data.map(function(score) {
return <Score
key={score.id}
id={score.id}
team1_name={score.team1_name}
team1_score={score.team1_score}
team2_name={score.team2_name}
team2_score={score.team2_score}
handleScoreRemove={this.handleScoreRemove.bind(this)}>
</Score>
}, this);
and in Score component call it like this
removeRecord: function(e) {
this.props.handleScoreRemove( /* add arguments what do you need */ );
},

call parent function from child
You don't (like what the other posts say). You pass handleScoreRemove into the child as a prop. Inside the child, you call the function by calling the prop. In the following, handleScoreRemove is passed as the onScoreRemove prop inside the child.
<Score ...stuff... onScoreRemove={this.handleScoreRemove}></Score>
You're already doing the same thing with the ScoreBox (parent) and ScoreForm (child). You're passing a reference of handleScoreSubmit as onScoreSubmit prop in the child.
<ScoreForm onScoreSubmit={this.handleScoreSubmit} />

You should pass handleScoreRemove as a prop to Score:
In ScoreList:
var scoreNodes = this.props.data.map(function(score) {
return (
<Score key={score.id} (...) handleScoreRemove={this.handleScoreRemove}>
</Score>
);
});
In Score:
removeRecord: function(e){
this.props.handleScoreRemove(this);
}

Understanding how Ajax success callback updates state in this ReactJS example

I am working thought the Reactjs Tutorial. I am trying to understand how the CommentForm component submits (or updates the server) with the data it has collected via passing it up to the CommentBox.
Here are the two components that work for reference:
var CommentForm = React.createClass({
handleSubmit: function(e) {
e.preventDefault();
var author = React.findDOMNode(this.refs.author).value.trim();
var text = React.findDOMNode(this.refs.text).value.trim();
if (!text || !author) {
return;
}
this.props.onCommentSubmit({author: author, text: text});
React.findDOMNode(this.refs.author).value = '';
React.findDOMNode(this.refs.text).value = '';
return;
},
render: function() {
return (
<form className="commentForm" onSubmit={this.handleSubmit}>
<input type="text" placeholder="Your name" ref="author" />
<input type="text" placeholder="Say something..." ref="text" />
<input type="submit" value="Post" />
</form>
);
}
});
var CommentBox = React.createClass({
loadCommentsFromServer: function() {
$.ajax({
url: this.props.url,
dataType: 'json',
cache: false,
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
handleCommentSubmit: function(comment) {
$.ajax({
url: this.props.url,
dataType: 'json',
type: 'POST',
data: comment,
success: function(data) {
this.setState({data: data});
}.bind(this),
error: function(xhr, status, err) {
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
getInitialState: function() {
return {data: []};
},
componentDidMount: function() {
this.loadCommentsFromServer();
setInterval(this.loadCommentsFromServer, this.props.pollInterval);
},
render: function() {
return (
<div className="commentBox">
<h1>Comments</h1>
<CommentList data={this.state.data} />
<CommentForm onCommentSubmit={this.handleCommentSubmit} />
</div>
);
}
});
My source of confusion comes from handleCommentSubmit in the CommentBox component, specifically the Ajax success callback.
Since we set data: comment, data is now merely the comment the form collected. But on success we take data and do this.setState({data: data});. Wouldn't that be setting the state to only one comment (the one we collected in the form?). Wouldn't we need to pull from the server to get all of the data, including the POST we just made with something like loadCommentsFromServer? How does this work?

Since we set data: comment, data is now merely the comment the form
collected. But on success we take data and do this.setState({data:
data});. Wouldn't that be setting the state to only one comment (the
one we collected in the form?).
No, in the example, the comment passed in to the function is setting the data property for the ajax request. The data parameter in the success callback is the data from the ajax response.
So, here they are setting the data state property to whatever the server responds with. I think the example assumes that the server is reflecting the same comment, but this allows the server to save the comment during the HTTP call.

React.js : Uncaught TypeError: undefined is not a function

I'm trying to learn react.js and found a tutorial online. I was following a react/rails tutorial from http://rny.io/rails/react/2014/07/31/reactjs-and-rails.html
The all the code was working fine until I got to the last step implementing the Comment Form. After following all the instructions, I get an error in my chrome console pointing to this line of code var commentNodes = this.props.comments.map(function (comment, index) { saying its "Uncaught TypeError: undefined is not a function". The form shows up and accepts input but nothing is displayed after I submit. Also, the tutorial is a bit dated, it is still using React.renderComponent, I changed it to React.render after reading the docs. Is there some more deprecated code I missed? or Can anyone help me or tell me what I did wrong?
Thanks in Advance
var Comment = React.createClass({
render: function () {
return (
<div className="comment">
<h2 className="commentAuthor">
{this.props.author}
</h2>
{this.props.comment}
</div>
);
}
});
var CommentList = React.createClass({
render: function () {
var commentNodes = this.props.comments.map(function (comment, index) {
return (
<Comment author={comment.author} comment={comment.comment} key={index} />
);
});
return (
<div className="commentList">
{commentNodes}
</div>
);
}
});
var CommentBox = React.createClass({
getInitialState: function () {
return {comments: []};
},
componentDidMount: function () {
this.loadCommentsFromServer();
},
loadCommentsFromServer: function () {
$.ajax({
url: this.props.url,
dataType: 'json',
success: function (comments) {
this.setState({comments: comments});
}.bind(this),
error: function (xhr, status, err) {
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
handleCommentSubmit: function(comment) {
var comments = this.state.comments;
var newComments = comments.concat([comment]);
this.setState({comments: newComments});
$.ajax({
url: this.props.url,
dataType: 'json',
type: 'POST',
data: {"comment": comment},
success: function(data) {
this.loadCommentsFromServer();
}.bind(this),
error: function(xhr, status, err) {
console.error(this.props.url, status, err.toString());
}.bind(this)
});
},
render: function () {
return (
<div className="commentBox">
<h1>Comments</h1>
<CommentList comments={this.state.comments} />
<CommentForm onCommentSubmit={this.handleCommentSubmit}/>
</div>
);
}
});
var CommentForm = React.createClass({
handleSubmit: function() {
var author = this.refs.author.getDOMNode().value.trim();
var comment = this.refs.comment.getDOMNode().value.trim();
this.props.onCommentSubmit({author: author, comment: comment});
this.refs.author.getDOMNode().value = '';
this.refs.comment.getDOMNode().value = '';
return false;
},
render: function() {
return (
<form className="commentForm" onSubmit={this.handleSubmit}>
<input type="text" placeholder="Your name" ref="author" />
<input type="text" placeholder="Say something..." ref="comment" />
<input type="submit" value="Post" />
</form>
);
}
});
var ready = function () {
React.render(
<CommentBox url="/comments.json" />,
document.getElementById('comments')
);
};
$(document).ready(ready);

The likely reason is that the comments coming back is not an array. Do a console.log(comments) or debugger; before this line: this.setState({comments: comments}); to check your ajax response and see if comments is an array of comments. If it's anything other than array, then that's your problem, you can just put some mock data in there for now until you can get that working.