How can I disable animation in a reactjs component first time - reactjs

I have a component with a list of items. I want each time I add or remove an item from the list to have animation. Everything it's OK with that.
My only problem is that I want to disable the animation first time when the component initialize.
http://jsfiddle.net/kb3gN/6887/
var ReactCSSTransitionGroup = React.addons.CSSTransitionGroup;
var Hello = React.createClass({
getInitialState: function () {
return {items: []};
},
addColor:function(){
this.setState({items:this.state.items.concat('new color')});
},
componentDidMount: function () {
var items = ['blue', 'red', 'green'];
this.setState({items: items});
},
render: function () {
var contentList = this.state.items.map(function (i,k) {
return (<li>{i}</li>);
});
return (
<div>
Hello <button onClick={this.addColor}>add</button>
<ReactCSSTransitionGroup transitionName="example">
{contentList}
</ReactCSSTransitionGroup>
</div>
)
}
});
React.render(<Hello name="World" />, document.body);
So, how can I make the animation appear only when changing the list and not ont the very first setState from didMount method?

Using componentWillMount instead of componentDidMount it will work perfectly as shown in this fiddle : http://jsfiddle.net/ghislaindj/jpuyd3gb/1/
However, if your real code must fetch the data in DidMount, you should use ssorallen comment.

Related

Rendering Firebase Data in React

I'm looking to render some firebase data to the HomeFeed component. I update the state in the componentDidMount method. You can see what that looks like below. It's an array. Should I just map over that using the map function? How do I access the specific info like "title", "link", "type", etc. to be able to render it?
Thanks a lot!
var React = require('react');
var Rebase = require('re-base');
var base = Rebase.createClass("https://nimbus-8ea70.firebaseio.com/");
// TODO: Render Firebase data to screen.
// Home
// <Home />
var HomeContainer = React.createClass({
render : function() {
return (
<div className="homeContainer">
<HomeFeed />
</div>
);
}
});
// Home Feed
// <HomeFeed />
var HomeFeed = React.createClass({
componentDidMount: function() {
base.fetch('article', {
context: this,
asArray: true,
then(data){
console.log(data);
this.setState({
feed: data
})
}
});
},
getInitialState: function() {
return {
feed: []
}
},
render : function() {
return (
<div className="homeFeed">
{/* Use map function here? */}
</div>
);
}
});
module.exports = HomeContainer;
render will run whenever state has been changed (unless you modify this behavior with, say, shouldComponentUpdate) so as long as you use setState properly your component will automatically update when its state changes.
If you're asking specifically how to turn an array into something that render understands, then yes, map is a very common way to do that. It might look something like this:
render : function() {
return (
<div className="homeFeed">
{this.state.feed.map(function(ea){
return <div>{ea.someProperty}</div>
})}
</div>
);
}
Note that you have to wrap ea.someProperty in curly braces because you're basically inserting JSX inside of a JavaScript expression inside of even more JSX. This kind of nested JSX/Expression/JSX structure is something you'll have to get comfortable with in React I'm afraid.
More about array.map

React, render single state/object multiple times

My real application, is to use react to create a firefox addon, to maintain an object/state in a DOM-less scope, and then render an element to the currently active browser window. Multiple browser windows are present.
So as a small experiment, to see if react can do this, I was messing around with the Timer example on the reactjs main site.
var Timer = React.createClass({
getInitialState: function() {
return {secondsElapsed: 0};
},
tick: function() {
this.setState({secondsElapsed: this.state.secondsElapsed + 1});
},
componentDidMount: function() {
this.interval = setInterval(this.tick, 1000);
},
componentWillUnmount: function() {
clearInterval(this.interval);
},
render: function() {
return (
<div>Seconds Elapsed: {this.state.secondsElapsed}</div>
);
}
});
var rendered = ReactDOM.render(<Timer />, mountNode);
// i hope to do something here to render it to another node
Is it possible to render the same timer to multiple nodes? The state should be same, and if i modify state in that single object it should affect both. Is this possible?
Thanks!
I actually tried a different method. I used a singleton object with an array of callbacks as a property. This array of callbacks stores innerMethods of all elements mounted which correspond to a particular event.
Ideally, you should do have a key value pair
event => [All functions to fire]
But for this example, I went for a rather primitive scenario where there is only one event. So it's just an array of call callbacks for that event(doSomething).
http://codepen.io/bhargav175/pen/rxNRxO
MyStore
let MyStore = {
doSomething : function(v){
MyStore.callbacks.forEach((callback)=>{
callback(v);
});
},
callbacks :[],
addSomethingListener : function(callback){
MyStore.callbacks.push(callback);
}
}
Everytime a component is mounted I do this,
componentDidMount(props){
MyStore.addSomethingListener(this.doStuff.bind(this));
}
which adds callbacks from each element to the Store and each of them gets fired when the event occurs.
Full code.
let MyStore = {
doSomething : function(v){
MyStore.callbacks.forEach((callback)=>{
callback(v);
});
},
callbacks :[],
addSomethingListener : function(callback){
MyStore.callbacks.push(callback);
}
}
/*
* A simple React component
*/
class Application extends React.Component {
constructor(props){
super(props);
this.state = {'some_prop':0};
}
doStuff(val){
this.setState({
'some_prop':val
});
}
componentDidMount(props){
MyStore.addSomethingListener(this.doStuff.bind(this));
}
render() {
return <div>
<h1>Hello, ES6 and React 0.13!</h1>
<p>
{this.state.some_prop}
</p>
</div>;
}
}
/*
* Render the above component into the div#app
*/
React.render(<Application />, document.getElementById('app'));
React.render(<Application />, document.getElementById('yetanotherapp'));
MyStore.doSomething(5);
MyStore.doSomething(15);
MyStore.doSomething(25);
So, if you see, I fire the doSomething event and all the components are updated at different mount nodes. In your case, you could move your tick logic into doSomething. Just a start. Hope this has helped.

React: Child communication in TodoList example

I'm learning React and modifying one of the tutorials. It's a Todo list, and I've come to a roadblock. I am trying to add the ability to delete items of the list. So I added an "x" to the end of each TodoList. But how can the child modify the parent's state.items? What is the "React" way of solving this?
var TodoList = React.createClass({
render: function() {
var createItem = function(itemText, index) {
return <li key={index + itemText}>{itemText} <a onClick={function() { // modify the parent item variable somehow?; }}>x</a></li>
};
return <ul>{this.props.items.map(createItem)}</ul>;
}
});
var TodoApp = React.createClass({
getInitialState: function() {
return {items: [], text: ''};
},
onChange: function(e) {
this.setState({text: e.target.value});
},
handleSubmit: function(e) {
e.preventDefault();
var nextItems = this.state.items.concat([this.state.text]);
var nextText = '';
this.setState({items: nextItems, text: nextText});
},
render: function() {
return (
<div>
<h3>TODO</h3>
<TodoList items={this.state.items} />
<form onSubmit={this.handleSubmit}>
<input onChange={this.onChange} value={this.state.text} />
<button>{'Add #' + (this.state.items.length + 1)}</button>
</form>
</div>
);
}
});
React.render(<TodoApp />, mountNode);
If you want to modify a parent's state from its child, you will need to create a function in your parent component that modifies the state in the way you want, then pass it to the child as a prop. Then, the child can just call this.props.functionName(args), and it will fire the function you created on the parent.
To follow your list example, let's say we have a List component that looks like this:
var List = React.createClass({
getInitialState : function () {
return ({items : []});
},
removeItem : function (num) {
var items = this.state.items;
items.splice(num, 1);
this.setState({items : items});
},
addItem : function () {
var value = React.findDOMNode(this.refs.itemName).value;
var items = this.state.items;
items.push(value);
this.setState({items : items});
},
render: function() {
var items = this.state.items.map(function(item, i) {
return <Item name={item} key={i} num={i} remove={this.removeItem} />
}.bind(this));
return (
<div>
List:<br/>
{items}
<br/>
<input type='text' ref='itemName'/>
<button onClick={this.addItem}>Add Item</button>
</div>
);
}
});
...and an Item component that looks like this:
var Item = React.createClass({
render : function () {
return (
<div>
{this.props.name}
<button onClick={this.props.remove.bind(null, this.props.num)}>Remove</button>
</div>
);
}
});
All this List does is hold on to the Items and provide an interface for which users can add and remove Items. Adding an Item is easy, we just need a button that, when clicked, takes the value of an <input> and adds it to our List's state. React will see the state transition and re-render the List for us, which will display the new Item.
Unlike adding an Item to the end of a list, the remove function needs to be a bit more specific regarding which Item needs to be removed. For that reason, we need a button on each Item that, when clicked, will remove the item from the list by calling this.props.remove and binding its num prop to the arguments. This will cause the removeItem function on List to fire, which will remove that item from our state. Again, React will see the state transition, and re-render our List for us, with the removed Item omitted.
Here is what that code looks like in action: https://jsfiddle.net/rxnpr9sq/
Hope that helps! Let me know if you have any additional questions.
I think this is what you need :https://facebook.github.io/react/tips/expose-component-functions.html
Michael Parker took the time to write your specific implementation this way.

How do I set state of sibling components easily in React?

I have got the beginnings of a clickable list component that will serve to drive a select element. As you can see from the below, onClick of the ListItem, I'm passing the state of a child element (ListItem in this case) to the parents (SelectableList, and CustomSelect component). This is working fine. However, what I would also like to do is change the state of the sibling components (the other ListItems) so that I can toggle their selected states when one of the ListItems is clicked.
At the moment, I'm simply using document.querySelectorAll('ul.cs-select li) to grab the elements and change the class to selected when it doesn't match the index of the clicked ListItem. This works - to an extent. However, after a few clicks, the state of the component has not been updated by React (only by client side JS), and things start to break down. What I would like to do is change the this.state.isSelected of the sibling list items, and use this state to refresh the SelectableList component. Could anyone offer a better alternative to what I've written below?
var React = require('react');
var SelectBox = require('./select-box');
var ListItem = React.createClass({
getInitialState: function() {
return {
isSelected: false
};
},
toggleSelected: function () {
if (this.state.isSelected == true) {
this.setState({
isSelected: false
})
} else {
this.setState({
isSelected: true
})
}
},
handleClick: function(listItem) {
this.toggleSelected();
this.props.onListItemChange(listItem.props.value);
var unboundForEach = Array.prototype.forEach,
forEach = Function.prototype.call.bind(unboundForEach);
forEach(document.querySelectorAll('ul.cs-select li'), function (el) {
// below is trying to
// make sure that when a user clicks on a list
// item in the SelectableList, then all the *other*
// list items get class="selected" removed.
// this works for the first time that you move through the
// list clicking the other items, but then, on the second
// pass through, starts to fail, requiring *two clicks* before the
// list item is selected again.
// maybe there's a better more "reactive" method of doing this?
if (el.dataset.index != listItem.props.index && el.classList.contains('selected') ) {
el.classList.remove('selected');
}
});
},
render: function() {
return (
<li ref={"listSel"+this.props.key}
data-value={this.props.value}
data-index={this.props.index}
className={this.state.isSelected == true ? 'selected' : '' }
onClick={this.handleClick.bind(null, this)}>
{this.props.content}
</li>
);
}
});
var SelectableList = React.createClass({
render: function() {
var listItems = this.props.options.map(function(opt, index) {
return <ListItem key={index} index={index}
value={opt.value} content={opt.label}
onListItemChange={this.props.onListItemChange.bind(null, index)} />;
}, this);
return <ul className="cs-select">{ listItems }</ul>;
}
})
var CustomSelect = React.createClass({
getInitialState: function () {
return {
selectedOption: ''
}
},
handleListItemChange: function(listIndex, listItem) {
this.setState({
selectedOption: listItem.props.value
})
},
render: function () {
var options = [{value:"One", label: "One"},{value:"Two", label: "Two"},{value:"Three", label: "Three"}];
return (
<div className="group">
<div className="cs-select">
<SelectableList options={options}
onListItemChange={this.handleListItemChange} />
<SelectBox className="cs-select"
initialValue={this.state.selectedOption}
fieldName="custom-select" options={options}/>
</div>
</div>
)
}
})
module.exports = CustomSelect;
The parent component should pass a callback to the children, and each child would trigger that callback when its state changes. You could actually hold all of the state in the parent, using it as a single point of truth, and pass the "selected" value down to each child as a prop.
In that case, the child could look like this:
var Child = React.createClass({
onToggle: function() {
this.props.onToggle(this.props.id, !this.props.selected);
},
render: function() {
return <button onClick={this.onToggle}>Toggle {this.props.label} - {this.props.selected ? 'Selected!' : ''}!</button>;
}
});
It has no state, it just fires an onToggle callback when clicked. The parent would look like this:
var Parent = React.createClass({
getInitialState: function() {
return {
selections: []
};
},
onChildToggle: function(id, selected) {
var selections = this.state.selections;
selections[id] = selected;
this.setState({
selections: selections
});
},
buildChildren: function(dataItem) {
return <Child
id={dataItem.id}
label={dataItem.label}
selected={this.state.selections[dataItem.id]}
onToggle={this.onChildToggle} />
},
render: function() {
return <div>{this.props.data.map(this.buildChildren)}</div>
}
});
It holds an array of selections in state and when it handles the callback from a child, it uses setState to re-render the children by passing its state down in the selected prop to each child.
You can see a working example of this here:
https://jsfiddle.net/fth25erj/
Another strategy for sibling-sibling communication is to use observer pattern.
The Observer Pattern is a software design pattern in which an object can send messages to multiple other objects.
No sibling or parent-child relationship is required to use this strategy.
Within the context of React, this would mean some components subscribe to receive particular messages and other components publish messages to those subscribers.
Components would typically subscribe in the componentDidMount method and unsubscribe in the componentWillUnmount method.
Here are 4 libraries that implement the Observer Pattern. The differences between them are subtle - EventEmitter is the most popular.
PubSubJS: "a topic-based publish/subscribe library written in JavaScript."
EventEmitter: "Evented JavaScript for the browser." It's actually an implementation of a library that already exists as part of nodejs core, but for the browser.
MicroEvent.js: "event emitter microlibrary - 20lines - for node and browser"
mobx: "Simple, scalable state management."
Taken from: 8 no-Flux strategies for React component communication which also is a great read in general.
The following code helps me to setup communication between two siblings. The setup is done in their parent during render() and componentDidMount() calls.
class App extends React.Component<IAppProps, IAppState> {
private _navigationPanel: NavigationPanel;
private _mapPanel: MapPanel;
constructor() {
super();
this.state = {};
}
// `componentDidMount()` is called by ReactJS after `render()`
componentDidMount() {
// Pass _mapPanel to _navigationPanel
// It will allow _navigationPanel to call _mapPanel directly
this._navigationPanel.setMapPanel(this._mapPanel);
}
render() {
return (
<div id="appDiv" style={divStyle}>
// `ref=` helps to get reference to a child during rendering
<NavigationPanel ref={(child) => { this._navigationPanel = child; }} />
<MapPanel ref={(child) => { this._mapPanel = child; }} />
</div>
);
}
}

Sending events between components

Consider the ToDo App example on the React homepage. For posterity, here's a fiddle and the code is at the end of this post.
Now say we decide to upgrade this app with w simple features:
Each todo item will have not only text, but also a "done" attribute. You can click on an item and it will toggle the "done" state, and perhaps add strikethrough styling when it is done.
At the very bottom, there will be text indicating the number of "Done", eg, "2 items done, 3 left to do"
The problem is that the state of the items is maintained in TodoApp, not in TodoList. So we'd like to add an onClick={something} to the <li> element in TodoList's render method. But we want that click event to be handled by TodoApp, which would then change the state of the item, and cause everything to re-render. If we wanted to approach it like this, how could we do it?
We could also create a TodoItem component to be called by TodoList, and push the statefulness down into that. This would allow the click to be handled by the TodoItem, but now we would need a way to share the TodoItems' states with the component indicating the number of items done and still todo.
In a nutshell, I'd like to know how components can send events to each other, because I think just knowing that would allow solutions to both problems.
React ToDo App
/** #jsx React.DOM */
var TodoList = React.createClass({
render: function() {
var createItem = function(itemText) {
return <li>{itemText}</li>;
};
return <ul>{this.props.items.map(createItem)}</ul>;
}
});
var TodoApp = React.createClass({
getInitialState: function() {
return {items: [], text: ''};
},
onChange: function(e) {
this.setState({text: e.target.value});
},
handleSubmit: function(e) {
e.preventDefault();
var nextItems = this.state.items.concat([this.state.text]);
var nextText = '';
this.setState({items: nextItems, text: nextText});
},
render: function() {
return (
<div>
<h3>TODO</h3>
<TodoList items={this.state.items} />
<form onSubmit={this.handleSubmit}>
<input onChange={this.onChange} value={this.state.text} />
<button>{'Add #' + (this.state.items.length + 1)}</button>
</form>
</div>
);
}
});
React.renderComponent(<TodoApp />, document.body);
The idiomatic way to do this is to pass a callback down to TodoList:
Live demo: http://jsbin.com/zeqizene/1/edit
I've changed TodoList to look like this:
var TodoList = React.createClass({
handleDoneToggle: function(i) {
this.props.onDoneToggle(i);
},
render: function() {
var createItem = function(item, i) {
return <li onClick={this.handleDoneToggle.bind(null, i)}>
{item.text}
{item.done && " (done)"}
</li>;
};
return <ul>{this.props.items.map(createItem, this)}</ul>;
}
});
When an item is clicked, TodoList will call its own onDoneToggle function, so TodoApp can modify the state appropriately.
See also Editing a rich data structure in React.js.

Resources