I would like to have a component, which get the property from parent component and make an AJAX request, based on this propery. The parent component can change this property and my child component must get another one AJAX request.
Here is my code, but I am not sure it is optimal and even correct:
<News source={this.state.currentSource} />
Component:
var News = React.createClass({
propTypes: {
source: React.PropTypes.string
},
getInitialState: function() {
return {
entities: []
};
},
componentWillReceiveProps(nextProps) {
var url = 'http://localhost:3000/api/sources/' + nextProps.source + '/news';
this.serverRequest = $.get(url, function(result) {
this.setState({
entities: result
});
}.bind(this));
},
componentWillUnmount: function() {
this.serverRequest.abort();
},
render: function() {
// ...
}});
module.exports = News;
Does componentWillReceiveProps is a good place for this code?
componentWillReceiveProps will work just fine, one thing I would do differently is if <News/> is getting its props from a parent component then a good pattern to follow is to have the parent component actually handle the api calls and pass down the results as props. This way your News component really only has to deal with rendering content based on its props vs rendering and managing state.
I can only see limited portion of your App so that might not fit your use case but here is a great article on doing that type of differentiation between smart and dumb components.
http://jaketrent.com/post/smart-dumb-components-react/
I've been playing a bit with ReactJS and am really enjoying the framework.
I'm also trying to follow the rule of creating components that are stateless where possible.
I have a Settings component that includes a child SettingsForm and a SettingsWidget.
Settings holds all the states, and only pass it as props to the form and widget.
This works (and scales) well because when the state in Settings is updated, it propagates to all child components.
var Settings = React.createClass({
getInitialState: function() {
settings: {}
}
})
What I am not 100% sure on is the best practice when accessing input values on SettingsForm to pass it on to the parent component.
I know I can use refs and also two-way binding to accomplish this, but neither feel very "ReactJS-like".
Is there a better of way accomplishing this that I am unaware of? For the sake of completeness, I've included the relevant code in my SettingsForm component below
var SettingsForm = React.createClass({
getInitialState: function() {
return {
changed: false
}
},
handleChange: function(event) {
this.setState({changed: true})
this.props.handleChange(
this.refs.emailInputFieldRef.getDOMNode().value,
this.refs.firstNameInputFieldRef.getDOMNode().value
)
},
handleSubmit: function(event) {
event.preventDefault();
// Access and pass on input values to parent callback so state is updated
this.props.handleUpdate(
this.refs.emailInputFieldRef.getDOMNode().value,
this.refs.firstNameInputFieldRef.getDOMNode().value
)
this.setState(this.getInitialState());
},
...
}
For now there is a Mixin you can use to link the input values to the state, called LinkedStateMixin that is exactly what you are looking for...
var WithLink = React.createClass({
mixins: [React.addons.LinkedStateMixin],
getInitialState: function() {
return {message: 'Hello!'};
},
render: function() {
return <input type="text" valueLink={this.linkState('message')} />;
}
});
Then all you have to do is modify your handler functions on the parent component to take your inputs as variables, and pass that function down to the child component as a prop. When you want to handle the form, call that function in the props and send the state (bound with from the Mixin) as the variables.
React Docs - React Link
I've read on http://scotch.io/tutorials/javascript/build-a-real-time-twitter-stream-with-node-and-react-js and it describes a technique of taking over server rendered React components seamlessly:
Server renders into {{{markup}}} in handlebars, and pass initial state.
<section id="react-app">{{{ markup }}}</div>
<script id="initial-state" type="application/json">{{{state}}}</script>
Then on the client side javascript
/** #jsx React.DOM */
var React = require('react');
var TweetsApp = require('./components/TweetsApp.react');
// Snag the initial state that was passed from the server side
var initialState = JSON.parse(document.getElementById('initial-state').innerHTML)
// Render the components, picking up where react left off on the server
React.renderComponent(
<TweetsApp tweets={initialState}/>,
document.getElementById('react-app')
);
But in a flux architecture, such as described in this article http://scotch.io/tutorials/javascript/creating-a-simple-shopping-cart-with-react-js-and-flux, state is initialized in the getInitialState lifecycle method:
// Method to retrieve state from Stores
function getCartState() {
return {
product: ProductStore.getProduct(),
selectedProduct: ProductStore.getSelected(),
cartItems: CartStore.getCartItems(),
cartCount: CartStore.getCartCount(),
cartTotal: CartStore.getCartTotal(),
cartVisible: CartStore.getCartVisible()
};
}
// Define main Controller View
var FluxCartApp = React.createClass({
// Get initial state from stores
getInitialState: function() {
return getCartState();
},
// Add change listeners to stores
componentDidMount: function() {
ProductStore.addChangeListener(this._onChange);
CartStore.addChangeListener(this._onChange);
},
// Remove change listers from stores
componentWillUnmount: function() {
ProductStore.removeChangeListener(this._onChange);
CartStore.removeChangeListener(this._onChange);
},
// Render our child components, passing state via props
render: function() {
return (
<div className="flux-cart-app">
<FluxCart products={this.state.cartItems} count={this.state.cartCount} total={this.state.cartTotal} visible={this.state.cartVisible} />
<FluxProduct product={this.state.product} cartitems={this.state.cartItems} selected={this.state.selectedProduct} />
</div>
);
},
// Method to setState based upon Store changes
_onChange: function() {
this.setState(getCartState());
}
});
module.exports = FluxCartApp;
Which one is the right approach to setting state from a progressive enhancement point of view?
Thinking about progressive enhancement I like how flux and react work together.
I am using ReactJS and Flux in my current project and everything is clean and easy. All you have to be aware of is showing some discipline of creating new stores when it really is needed. I dont really like the eventEmitter stuff though. I just trigger my own events which I define in a seperate eventConstants.js file this allows me to have several components listening for different changes on the same store.
This really scales well.
Answering your question:
It does depend about your usecase. Ignoring that rendering an initial page on the server is great for SEO it does only make sence to render on the server if users should all see pretty much the same content. I like to keep client stuff on the client.
I hope this helped you
This may be treading that line between answerable and opinionated, but I'm going back and forth as to how to structure a ReactJS component as complexity grows and could use some direction.
Coming from AngularJS, I want to pass my model into the component as a property and have the component modify the model directly. Or should I be splitting the model up into various state properties and compiling it back together when sending back upstream? What is the ReactJS way?
Take the example of a blog post editor. Trying to modify the model directly ends up looking like:
var PostEditor = React.createClass({
updateText: function(e) {
var text = e.target.value;
this.props.post.text = text;
this.forceUpdate();
},
render: function() {
return (
<input value={this.props.post.text} onChange={this.updateText}/>
<button onClick={this.props.post.save}/>Save</button>
);
}
});
Which seems wrong.
Is it more the React way to make our text model property state, and compile it back into the model before saving like:
var PostEditor = React.createClass({
getInitialState: function() {
return {
text: ""
};
},
componentWillMount: function() {
this.setState({
text: this.props.post.text
});
},
updateText: function(e) {
this.setState({
text: e.target.value
});
},
savePost: function() {
this.props.post.text = this.state.text;
this.props.post.save();
},
render: function() {
return (
<input value={this.state.text} onChange={this.updateText}/>
<button onClick={this.savePost}/>Save</button>
);
}
});
This doesn't require a call to this.forceUpdate(), but as the model grows, (a post may have an author, subject, tags, comments, ratings, etc...) the component starts getting really complicated.
Is the first method with ReactLink the way to go?
Updating 2016:
React is changed, and explanation "props vs state" became very simple. If a component needs to change data - put it in a state, otherwise in props. Because props are read-only now.
What's the exact difference between props and state?
You can find good explanation here (full version)
Your second approach is more like it. React doesn't care about models so much as it cares about values and how they flow through your app. Ideally, your post model would be stored in a single component at the root. You then create child components that each consume parts of the model.
You can pass callbacks down to the children that need to modify your data, and call them from the child component.
Modifying this.props or this.state directly is not a good idea, because React will not be able to pick up on the changes. That's because React does a shallow comparison of your post prop to determine if it has changed.
I made this jsfiddle to show how data could flow from an outer to an inner component.
The handleClick method shows 3 ways to (im)properly update state:
var Outer = React.createClass({
getInitialState: function() {
return {data: {value: 'at first, it works'}};
},
handleClick: function () {
// 1. This doesn't work, render is not triggered.
// Never set state directly because the updated values
// can still be read, which can lead to unexpected behavior.
this.state.data.value = 'but React will never know!';
// 2. This works, because we use setState
var newData = {value: 'it works 2'};
this.setState({data: newData});
// 3. Alternatively you can use React's immutability helpers
// to update more complex models.
// Read more: http://facebook.github.io/react/docs/update.html
var newState = React.addons.update(this.state, {
data: {value: {$set: 'it works'}}
});
this.setState(newState);
},
render: function() {
return <Inner data={this.state.data} handleClick={this.handleClick} />;
}
});
From React doc
props are immutable: they are passed from the parent and are "owned" by the parent. To implement interactions, we introduce mutable state to the component. this.state is private to the component and can be changed by calling this.setState(). When the state is updated, the component re-renders itself.
From TrySpace: when props (or state) are updated (via setProps/setState or parent) the component re-renders as well.
A reading from Thinking in React:
Let's go through each one and figure out which one is state. Simply
ask three questions about each piece of data:
Is it passed in from a parent via props? If so, it probably isn't
state.
Does it change over time? If not, it probably isn't state.
Can you compute it based on any other state or props in your
component? If so, it's not state.
I'm not sure if I'm answering your question, but I've found that, especially in a large/growing application, the Container/Component pattern works incredibly well.
Essentially you have two React components:
a "pure" display component, which deals with styling and DOM interaction;
a container component, which deals with accessing/saving external data, managing state, and rendering the display component.
Example
N.B. This example is a probably too simple to illustrate the benefits of this pattern, as it is quite verbose for such a straightforward case.
/**
* Container Component
*
* - Manages component state
* - Does plumbing of data fetching/saving
*/
var PostEditorContainer = React.createClass({
getInitialState: function() {
return {
text: ""
};
},
componentWillMount: function() {
this.setState({
text: getPostText()
});
},
updateText: function(text) {
this.setState({
text: text
});
},
savePost: function() {
savePostText(this.state.text);
},
render: function() {
return (
<PostEditor
text={this.state.text}
onChange={this.updateText.bind(this)}
onSave={this.savePost.bind(this)}
/>
);
}
});
/**
* Pure Display Component
*
* - Calculates styling based on passed properties
* - Often just a render method
* - Uses methods passed in from container to announce changes
*/
var PostEditor = React.createClass({
render: function() {
return (
<div>
<input type="text" value={this.props.text} onChange={this.props.onChange} />
<button type="button" onClick={this.props.onSave} />
</div>
);
}
});
Benefits
By keeping display logic and data/state management separate, you have a re-usable display component which:
can easily be iterated with different sets of props using something like react-component-playground
can be wrapped with a different container for different behavior (or combine with other components to build larger parts of your application
You also have a container component which deals with all external communication. This should make it easier to be flexible about the way you access your data if you make any serious changes later on*.
This pattern also makes writing and implementing unit tests a lot more straightforward.
Having iterated a large React app a few times, I've found that this pattern keeps things relatively painless, especially when you have larger components with calculated styles or complicated DOM interactions.
*Read up on the flux pattern, and take a look at Marty.js, which largely inspired this answer (and I have been using a lot lately) Redux (and react-redux), which implement this pattern extremely well.
Note for those reading this in 2018 or later:
React has evolved quite a bit since this answer was written, especially with the introduction of Hooks. However, the underlying state management logic from this example remains the same, and more importantly, the benefits that you get from keeping your state and presentation logic separate still apply in the same ways.
I think you're using an anti-pattern which Facebook has already explained at this link
Here's thing you're finding:
React.createClass({
getInitialState: function() {
return { value: { foo: 'bar' } };
},
onClick: function() {
var value = this.state.value;
value.foo += 'bar'; // ANTI-PATTERN!
this.setState({ value: value });
},
render: function() {
return (
<div>
<InnerComponent value={this.state.value} />
<a onClick={this.onClick}>Click me</a>
</div>
);
}
});
The first time the inner component gets rendered, it will have { foo: 'bar' } as the value prop. If the user clicks on the anchor, the parent component's state will get updated to { value: { foo: 'barbar' } }, triggering the re-rendering process of the inner component, which will receive { foo: 'barbar' } as the new value for the prop.
The problem is that since the parent and inner components share a reference to the same object, when the object gets mutated on line 2 of the onClick function, the prop the inner component had will change. So, when the re-rendering process starts, and shouldComponentUpdate gets invoked, this.props.value.foo will be equal to nextProps.value.foo, because in fact, this.props.value references the same object as nextProps.value.
Consequently, since we'll miss the change on the prop and short circuit the re-rendering process, the UI won't get updated from 'bar' to 'barbar'
I'm trying to working with backbone but I'm missing it's base concepts because this is the first JavaScript MVVM Framework I try.
I've taken a look to some guide but I think I still missing how it should be used.
I'll show my app to get some direction:
// Search.js
var Search = {
Models: {},
Collections: {},
Views: {},
Templates:{}
};
Search.Models.Product = Backbone.Model.extend({
defaults: search.product.defaults || {},
toUrl:function (url) {
// an example method
return url.replace(" ", "-").toLowerCase();
},
initialize:function () {
console.log("initialize Search.Models.Product");
}
});
Search.Views.Product = Backbone.View.extend({
initialize:function () {
console.log("initialize Search.Views.Product");
},
render:function (response) {
console.log("render Search.Views.Product");
console.log(this.model.toJSON());
// do default behavior here
}
});
Search.Models.Manufacturer = Backbone.Model.etc...
Search.Views.Manufacturer = Backbone.View.etc...
then in my web application view:
<head>
<script src="js/jquery.min.js"></script>
<script src="js/underscore.min.js"></script>
<script src="js/backbone/backbone.min.js"></script>
<script src="js/backbone/Search.js"></script>
</head>
<body>
<script>
var search = {};
search.product = {};
search.product.defaults = {
id:0,
container:"#search-results",
type:"product",
text:"<?php echo __('No result');?>",
image:"<?php echo $this->webroot;?>files/product/default.png"
};
$(function(){
var ProductModel = new Search.Models.Product();
var ProductView = new Search.Views.Product({
model:ProductModel,
template:$("#results-product-template"),
render:function (response) {
// do specific view behavior here if needed
console.log('render ProductView override Search.Views.Product');
}
});
function onServerResponse (ajax_data) {
// let's assume there is some callback set for onServerResponse method
ProductView.render(ajax_data);
}
});
</script>
</body>
I think I missing how Backbone new instances are intended to be used for, I thought with Backbone Search.js I should build the base app like Search.Views.Product and extend it in the view due to the situation with ProductView.
So in my example, with render method, use it with a default behavior in the Search.js and with specific behavior in my html view.
After some try, it seems ProductModel and ProductView are just instances and you have to do all the code in the Search.js without creating specific behaviors.
I understand doing it in this way make everything easiest to be kept up to date, but what if I use this app in different views and relative places?
I'm sure I'm missing the way it should be used.
In this guides there is no code used inside the html view, so should I write all the code in the app without insert specific situations?
If not, how I should write the code for specific situations of the html view?
Is it permitted to override methods of my Backbone application?
Basically, you should think of the different parts like this:
templates indicate what should be displayed and where. They are writtent in HTML
views dictate how the display should react to changes in the environment (user clicks, data changing). They are written in javascript
models and collections hold the data and make it easier to work with. For example, if a model is displayed in a view, you can tell the view to refresh when the model's data changes
then, you have javascript code that will create new instances of views with the proper model/collection and display them in the browser
I'm writing a book on Marionette.js, which is a framework to make working with Backbone easier. The first chapters are available in a free sample, and explain the above points in more detail: http://samples.leanpub.com/marionette-gentle-introduction-sample.pdf