I'm recently working on react.js, and now I have two problems:
The file structure is like
>public
>src
>components
>img
x.png
Item.js
App.js
index.js
Item.js:
import React from 'react';
class Item extends React.Component{
constructor(props){
super(props);
}
render(){
return(
<li className="todo-app__item">
<div className="todo-app__checkbox">
<input type="checkbox" id={this.props.num}
checked={this.props.completed} onClick = {this.props.onClick}/>
<label htmlFor={this.props.num}></label>
</div>
<h1 className="todo-app__item-detail">{this.props.text}</h1>
<img src='./components/img/x.png' className="todo-app__item-x"/>
</li>
);
}
}
export default Item;
App.js
import './App.css';
import React from 'react';
import Item from './components/Item.js';
class Main extends React.Component{
constructor(props){
super(props);
this.state={tasks: []}
}
handleKeyDown = (e)=>{
if (e.key === 'Enter') {
this.setState (prevState => ({
tasks: [...prevState.tasks, {content: e.target.value, completed: false}]
}));
}
}
handleClick = (e) =>{
this.setState (prevState => {
let newTasks = prevState.tasks.slice();
newTasks[e].completed = !prevState.tasks[e].completed;
return{tasks: newTasks};
})
}
/*displayAll = () =>{
}
displayActive = () =>{
}
displayCompleted = () =>{
}
deleteCompleted = () =>{
}*/
render(){
return(
<section className="todo-app__main">
<input className="todo-app__input"
placeholder="What needs to be done?" onKeyDown={this.handleKeyDown} />
<ul className="todo-app__list" id="todo-list">
{this.state.tasks.map(item =>
<Item num={this.state.tasks.indexOf(item)} text={item.content} completed={item.completed}
onClick={() => this.handleClick(this.state.tasks.indexOf(item))}/>)}
</ul>
<footer className="todo-app__footer" id="todo-footer">
<div className="todo-app__total"> {this.state.tasks.filter(e=>e.completed===false).length} Left</div>
<ul className="todo-app__view-buttons">
<button>All</button>
<button>Active</button>
<button>Complete</button>
</ul>
<div className="todo-app__clean">
<button>Clear complete</button>
</div>
</footer>
</section>
);
}
}
My x.png is not showing properly. How to fix it?
The three buttons in the bottom, I hope that completed can do something like displaying the task that satisfies task[1]=true without deleting the item. How do I implement this?
You can modify the src attribute of img, the relative path is wrong now
<img src='./img/x.png' className="todo-app__item-x"/>
Use react state to render different buttons
{this.state.tasks[x].completed && <button>Complete</button>}
eg: when tasks x is completed, display button.
I have to change(add) className on the first div, after click on "icon-caret-down".
My code doesn't work.
Can you give me some tips?
export default class Nav extends React.Component {
render() {
var btnClass = classNames({
'nav-conteiner': true,
'nav-conteiner-mob': this.state.isPressed
});
return (
<div classNames={btnClass}>
<span className='icon-soundcloud'></span>
<h6 id="site-name">SoundCloud</h6>
<span className="icon-caret-down" onClick={this.openSerch.bind(this)}></span>
<ul>
<li><a href='#'>Explore</a></li>
<li><a href='#'>Playlist</a></li>
</ul>
<Search/>
</div>
);
}
openSerch(){
console.log('hello');
this.setState({isPressed:true});
}
}
I guess the main error that you didn't announce initial state.
The next thing, that you used wrong attribute "classNames" instead "className" to wrapper.
I corrected mistakes, check it out:
export default class Nav extends React.Component {
constructor (props) {
super(props);
this.state = {
isPressed: false
}
}
render () {
var btnClass = classNames({
'nav-conteiner': true,
'nav-conteiner-mob': this.state.isPressed
});
return (
<div className={btnClass}>
<span className='icon-soundcloud'></span>
<h6 id="site-name">SoundCloud</h6>
<span className="icon-caret-down" onClick={this.openSerch.bind(this)}></span>
<ul>
<li><a href='#'>Explore</a></li>
<li><a href='#'>Playlist</a></li>
</ul>
<Search/>
</div>
);
}
openSerch () {
this.setState({ isPressed: true });
}
}
export default class Nav extends React.Component {
constructor (props) {
super(props);
this.state = {
isPressed: false
}
}
render() {
var btnClass = classNames({
'nav-conteiner': true,
'nav-conteiner-mob': this.state.isPressed
});
return (
<div classNames={this.state.isPressed ? btnActiveClass :btnClass }>
<span className='icon-soundcloud'></span>
<h6 id="site-name">SoundCloud</h6>
<span className="icon-caret-down" onClick={this.openSerch.bind(this)}></span>
<ul>
<li><a href='#'>Explore</a></li>
<li><a href='#'>Playlist</a></li>
</ul>
<Search/>
</div>
);
}
openSerch(){
console.log('hello');
this.setState({isPressed:true});
}
}
I am working with ReactJS at the moment (I am very much a beginner). What I wanting to do is show/hide a menu component when a link is clicked in the site navigation. The menu is being built as a component that sits within a component (header).
The user clicks the menu button and that then toggles the menu to be shown or hidden, I am however having problems working out where the logic to show and hide the menu component should live the showing an hiding is relatively simple I basically want to add and remove a class to the menu component to show or hide it.
I have a similar show/hide working for my login and register forms, but the show and hide classes for these are added in the header component not the child component, here is my header component JS so far.
import React, { Component } from 'react'
import PropTypes from 'prop-types'
import Menu from './menu';
import LoginForm from '../Login';
import RegisterForm from '../Register';
export default class Explore extends Component {
constructor(props) {
super(props);
this.state = {
loginMenuVisible : false,
registerMenuVisible : false,
mainMenuVisible : false
};
console.log(this.state);
//this.triggerMenu = this.triggerMenu.bind(this);
}
render() {
return (
<div className="site__navigation">
<Menu />
<header className="site__header">
<img src="img/logo-full-color.png" alt="meatFree" />
<ul className="header__navigation">
<li className="header__navigation__item">
<a href="/register" onClick={this.toggleMenu.bind(this, 'register')}>Register</a>
<ul className={this.state.registerMenuVisible ? "dropdown visible" : "dropdown"}>
<li>
<LoginForm />
</li>
</ul>
</li>
<li className="header__navigation__item">
<a href="#" onClick={this.toggleMenu.bind(this, 'login')}>Login</a>
<ul className={this.state.loginMenuVisible ? "dropdown visible" : "dropdown"}>
<li>
<LoginForm />
</li>
</ul>
</li>
<li className="header__navigation__item">
<a href="" className="nav__toggle">
Menu
</a>
</li>
</ul>
</header>
</div>
);
}
toggleMenu(type, e) {
e.preventDefault();
console.log(type);
switch(type) {
case 'login':
if(this.state.loginMenuVisible) {
this.setState({loginMenuVisible : false});
} else {
this.setState({
registerMenuVisible : false,
loginMenuVisible : true
});
}
break;
case 'register':
if(this.state.registerMenuVisible) {
this.setState({registerMenu : false});
} else {
this.setState({
registerMenuVisible : true
});
}
break;
case 'menu':
this.setState({mainMenuVisible : true });
}
}
}
AS you see I have a element in the state called mainMenuVisible, I want to be able to maniuplate this within the Menu component.
I like to keep things simple:
export default class Example extends Component {
constructor(){
super(props)
this.state = {
showMenu: false
}
this.menuShowToggle = this.menuShowToggle.bind(this);
}
menuShowToggle = () => {
this.setState({showMenu: !this.state.showMenu})
}
render = () => {
return (
<div>
<div className={this.state.showMenu ? 'showMenu': 'hideMenu'}>Hidden Menu</div>
<button type="button" onClick={this.menuShowToggle} value="toggle" />
</div>
)
}
}
To achieve this using your current setup, you could pass the toggleMenu() function as a prop to your rendered Menu component
<Menu toggleMenu={this.toggleMenu} />
Then within the Menu component, you could call toggleMenu() in a click handler and pass in 'menu' as the type.
If you are using ReactJs you should consider the following pattern:
1. Set a state specifically to show/hide the the menu
2. Create a function which will toggle the state
3. Add a conditional rendering for the component menu
Here is how the the code can be done:
Step 1.
constructor(props) {
super(props);
this.state = {
isComponenetMenuVisisble : false, // by default to disable it
};
}
Step 2.
toggleComponentMenu = () => {
const isComponenetMenuVisisble = !this.state.isComponenetMenuVisisble;
this.setState({ isComponenetMenuVisisble });
}
Step 3.
{this.state.isComponenetMenuVisisble && <Menu />}
// if isComponenetMenuVisisble is true render <Menu />
And then you can add the event handler like the following
<div className="your-element" onClick={this.toggleComponentMenu}>
... your stuff
</div>
A good point to highlight in the code above is that I am using a method rather than a function in step 2. When using a method instead of a function there will be no need to bind the function on event handlers because this context will be the class itself. Much more details can be found about this in here http://blog.andrewray.me/react-es6-autobinding-and-createclass/
I'm new to ReactJS and trying to make a small web application.
I have a list of items to put in a sidebar, and I want each item to give back a status tu the sidebar when clicked (so that I can style the active link accordingly).
import React, {Component} from 'react';
import SideBarItem from "./SideBarItem";
const items = {
'DASHBOARD' : 'home',
'Utenti': 'user',
'Corsi' : 'education',
'Logistica' : 'check',
'Comunicazioni': 'bullhorn'
};
const listItems = Object.entries(items).map(([key,value])=>{
return <SideBarItem
onClick={this.changeState(key)} active={this.state.active == key ? 'active' : ''}
title={key}
glyph={'glyphicon glyphicon-' + value.toString()}/>
});
class SideBar extends Component {
constructor(props) {
super(props);
this.state = {active: 'DASHBOARD'};
}
changeState (row) {
this.setState({
active: row
});
}
render() {
return (
<div id = "sidebar" className="col-sm-3 col-md-2 sidebar paper-depth-1">
<ul className = 'nav nav-sidebar'>
{listItems}
</ul>
</div>
);
}
}
export default SideBar;
But this code is returnig the following error:
TypeError: _this.changeState is not a function
I understand that there's something wrong in calling a component function from an outside variable, but I don't get how can I make this work in any other way.
If you create the list of items in render(), the this scope will be the component instance, as you need it to be.
class SideBar extends Component {
constructor(props) {
super(props);
this.state = {active: 'DASHBOARD'};
}
changeState(row) {
this.setState({
active: row
});
}
render() {
return (
<div id="sidebar" className="col-sm-3 col-md-2 sidebar paper-depth-1">
<ul className="nav nav-sidebar">
{Object.entries(items).map(([key,value]) =>
<SideBarItem
onClick={() => this.changeState(key)}
active={this.state.active == key ? 'active' : ''}
title={key}
glyph={'glyphicon glyphicon-' + value.toString()}
/>
)}
</ul>
</div>
);
}
}
I have
var TestApp = React.createClass({
getComponent: function(){
console.log(this.props);
},
render: function(){
return(
<div>
<ul>
<li onClick={this.getComponent}>Component 1</li>
</ul>
</div>
);
}
});
React.renderComponent(<TestApp />, document.body);
I want to color the background of the clicked list element. How can I do this in React ?
Something like
$('li').on('click', function(){
$(this).css({'background-color': '#ccc'});
});
Why not:
onItemClick: function (event) {
event.currentTarget.style.backgroundColor = '#ccc';
},
render: function() {
return (
<div>
<ul>
<li onClick={this.onItemClick}>Component 1</li>
</ul>
</div>
);
}
And if you want to be more React-ive about it, you might want to set the selected item as state of its containing React component, then reference that state to determine the item's color within render:
onItemClick: function (event) {
this.setState({ selectedItem: event.currentTarget.dataset.id });
//where 'id' = whatever suffix you give the data-* li attribute
},
render: function() {
return (
<div>
<ul>
<li onClick={this.onItemClick} data-id="1" className={this.state.selectedItem == 1 ? "on" : "off"}>Component 1</li>
<li onClick={this.onItemClick} data-id="2" className={this.state.selectedItem == 2 ? "on" : "off"}>Component 2</li>
<li onClick={this.onItemClick} data-id="3" className={this.state.selectedItem == 3 ? "on" : "off"}>Component 3</li>
</ul>
</div>
);
},
You'd want to put those <li>s into a loop, and you need to make the li.on and li.off styles set your background-color.
Two ways I can think of are
var TestApp = React.createClass({
getComponent: function(index) {
$(this.getDOMNode()).find('li:nth-child(' + index + ')').css({
'background-color': '#ccc'
});
},
render: function() {
return (
<div>
<ul>
<li onClick={this.getComponent.bind(this, 1)}>Component 1</li>
<li onClick={this.getComponent.bind(this, 2)}>Component 2</li>
<li onClick={this.getComponent.bind(this, 3)}>Component 3</li>
</ul>
</div>
);
}
});
React.renderComponent(<TestApp /> , document.getElementById('soln1'));
This is my personal favorite.
var ListItem = React.createClass({
getInitialState: function() {
return {
isSelected: false
};
},
handleClick: function() {
this.setState({
isSelected: true
})
},
render: function() {
var isSelected = this.state.isSelected;
var style = {
'background-color': ''
};
if (isSelected) {
style = {
'background-color': '#ccc'
};
}
return (
<li onClick={this.handleClick} style={style}>{this.props.content}</li>
);
}
});
var TestApp2 = React.createClass({
getComponent: function(index) {
$(this.getDOMNode()).find('li:nth-child(' + index + ')').css({
'background-color': '#ccc'
});
},
render: function() {
return (
<div>
<ul>
<ListItem content="Component 1" />
<ListItem content="Component 2" />
<ListItem content="Component 3" />
</ul>
</div>
);
}
});
React.renderComponent(<TestApp2 /> , document.getElementById('soln2'));
Here is a DEMO
I hope this helps.
Here is how you define a react onClick event handler, which was answering the question title... using es6 syntax
import React, { Component } from 'react';
export default class Test extends Component {
handleClick(e) {
e.preventDefault()
console.log(e.target)
}
render() {
return (
<a href='#' onClick={e => this.handleClick(e)}>click me</a>
)
}
}
Use ECMA2015. Arrow functions make "this" a lot more intuitive.
import React from 'react';
class TestApp extends React.Component {
getComponent(e, index) {
$(e.target).css({
'background-color': '#ccc'
});
}
render() {
return (
<div>
<ul>
<li onClick={(e) => this.getComponent(e, 1)}>Component 1</li>
<li onClick={(e) => this.getComponent(e, 2)}>Component 2</li>
<li onClick={(e) => this.getComponent(e, 3)}>Component 3</li>
</ul>
</div>
);
}
});
React.renderComponent(<TestApp /> , document.getElementById('soln1'));`
If you're using ES6, here's some simple example code:
import React from 'wherever_react_is';
class TestApp extends React.Component {
getComponent(event) {
console.log('li item clicked!');
event.currentTarget.style.backgroundColor = '#ccc';
}
render() {
return(
<div>
<ul>
<li onClick={this.getComponent.bind(this)}>Component 1</li>
</ul>
</div>
);
}
}
export default TestApp;
In ES6 class bodies, functions no longer require the 'function' keyword and they don't need to be separated by commas. You can also use the => syntax as well if you wish.
Here's an example with dynamically created elements:
import React from 'wherever_react_is';
class TestApp extends React.Component {
constructor(props) {
super(props);
this.state = {
data: [
{name: 'Name 1', id: 123},
{name: 'Name 2', id: 456}
]
}
}
getComponent(event) {
console.log('li item clicked!');
event.currentTarget.style.backgroundColor = '#ccc';
}
render() {
<div>
<ul>
{this.state.data.map(d => {
return(
<li key={d.id} onClick={this.getComponent.bind(this)}>{d.name}</li>
)}
)}
</ul>
</div>
);
}
}
export default TestApp;
Note that each dynamically created element should have a unique reference 'key'.
Furthermore, if you would like to pass the actual data object (rather than the event) into your onClick function, you will need to pass that into your bind. For example:
New onClick function:
getComponent(object) {
console.log(object.name);
}
Passing in the data object:
{this.state.data.map(d => {
return(
<li key={d.id} onClick={this.getComponent.bind(this, d)}>{d.name}</li>
)}
)}
Handling events with React elements is very similar to handling events
on DOM elements. There are some syntactic differences:
React events are named using camelCase, rather than lowercase.
With JSX you pass a function as the event handler, rather than a string.
So as mentioned in React documentation, they quite similar to normal HTML when it comes to Event Handling, but event names in React using camelcase, because they are not really HTML, they are JavaScript, also, you pass the function while we passing function call in a string format for HTML, they are different, but the concepts are pretty similar...
Look at the example below, pay attention to the way event get passed to the function:
function ActionLink() {
function handleClick(e) {
e.preventDefault();
console.log('The link was clicked.');
}
return (
<a href="#" onClick={handleClick}>
Click me
</a>
);
}
import React from 'react';
class MyComponent extends React.Component {
getComponent(event) {
event.target.style.backgroundColor = '#ccc';
// or you can write
//arguments[0].target.style.backgroundColor = '#ccc';
}
render() {
return(
<div>
<ul>
<li onClick={this.getComponent.bind(this)}>Component 1</li>
</ul>
</div>
);
}
}
export { MyComponent }; // use this to be possible in future imports with {} like: import {MyComponent} from './MyComponent'
export default MyComponent;
class FrontendSkillList extends React.Component {
constructor() {
super();
this.state = { selectedSkill: {} };
}
render() {
return (
<ul>
{this.props.skills.map((skill, i) => (
<li
className={
this.state.selectedSkill.id === skill.id ? "selected" : ""
}
onClick={this.selectSkill.bind(this, skill)}
style={{ cursor: "pointer" }}
key={skill.id}
>
{skill.name}
</li>
))}
</ul>
);
}
selectSkill(selected) {
if (selected.id !== this.state.selectedSkill.id) {
this.setState({ selectedSkill: selected });
} else {
this.setState({ selectedSkill: {} });
}
}
}
const data = [
{ id: "1", name: "HTML5" },
{ id: "2", name: "CSS3" },
{ id: "3", name: "ES6 & ES7" }
];
const element = (
<div>
<h1>Frontend Skill List</h1>
<FrontendSkillList skills={data} />
</div>
);
ReactDOM.render(element, document.getElementById("root"));
.selected {
background-color: rgba(217, 83, 79, 0.8);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>
#user544079 Hope this demo can help :) I recommend changing background color by toggling classname.
import React from 'react';
class MyComponent extends React.Component {
getComponent(event) {
event.target.style.backgroundColor = '#ccc';
// or you can write
//arguments[0].target.style.backgroundColor = '#ccc';
}
render() {
return(
<div>
<ul>
<li onClick={this.getComponent.bind(this)}>Component 1</li>
</ul>
</div>
);
}
}
export { MyComponent }; // use this to be possible in future imports with {} like: import {MyComponent} from './MyComponent'
export default MyComponent;
You can make use of the React.createClone method. Create your element, than create a clone of it. During the clone's creation, you can inject props. Inject an onClick : method prop like this
{ onClick : () => this.changeColor(originalElement, index) }
the changeColor method will set the state with the duplicate, allowing you sto set the color in the process.
render()
{
return(
<ul>
{this.state.items.map((val, ind) => {
let item = <li key={ind}>{val}</li>;
let props = {
onClick: () => this.Click(item, ind),
key : ind,
ind
}
let clone = React.cloneElement(item, props, [val]);
return clone;
})}
</ul>
)
}
This is a non-standard (but not so uncommon) React pattern that doesn't use JSX, instead putting everything inline. Also, it's Coffeescript.
The 'React-way' to do this would be with the component's own state:
(c = console.log.bind console)
mock_items: [
{
name: 'item_a'
uid: shortid()
}
{
name: 'item_b'
uid: shortid()
}
{
name: 'item_c'
uid: shortid()
}
]
getInitialState: ->
lighted_item: null
render: ->
div null,
ul null,
for item, idx in #mock_items
uid = item.uid
li
key: uid
onClick: do (idx, uid) =>
(e) =>
# justf to illustrate these are bound in closure by the do lambda,
c idx
c uid
#setState
lighted_item: uid
style:
cursor: 'pointer'
background: do (uid) =>
c #state.lighted_item
c 'and uid', uid
if #state.lighted_item is uid then 'magenta' else 'chartreuse'
# background: 'chartreuse'
item.name
This example works -- I tested it locally.
You can check out this example code exactly at my github.
Originally the env was only local for my own whiteboard r&d purposes but I posted it to Github for this. It may get written over at some point but you can check out the commit from Sept 8, 2016 to see this.
More generally, if you want to see how this CS/no-JSX pattern for React works, check out some recent work here. It's possible I will have time to fully implement a POC for this app idea, the stack for which includes NodeJS, Primus, Redis, & React.