http://jsfiddle.net/1erw4fba/5/
var App = React.createClass({
getInitialState(){
return {
items:[1,2,3],
isEditing:false
}
},
dlt_item(key){
var newItems = this.state.items.filter((item,i)=> i !== key)
this.setState({items:newItems,isEditing:false})
},
edit_handler(){
this.setState({isEditing:true})
},
isEditing_html(){
return(
<div>
<input type="text" />
<button>Save</button>
</div>
)
},
renderItem(){
return(
this.state.items.map(function(item,i) {
var temp = null;
if(this.state.isEditing){
temp = this.isEditing_html()
}else{
temp = <div onClick={this.edit_handler}><button>Edit</button>
<button onClick={this.dlt_item.bind(this,i)}>Delete</button></div>
}
return (<li key={i}>{item}
{temp}
</li>
)
}.bind(this)
)
)
},
render(){
return(
<ul>
{this.renderItem()}
</ul>
)
}
})
When I click delete button, why the edit input text appear? suppose it will only appear if the state of isEditing is true. Then I try to purposely set that to false, but still it appear. This is unusual to me.
Your problem is here:
temp = <div onClick={this.edit_handler}><button>Edit</button>
<button onClick={this.dlt_item.bind(this,i)}>Delete</button></div>
You put the onClick in the div, so it's called both when you press the Edit button or the Delete button. Just use:
temp = <div><button onClick={this.edit_handler}>Edit</button>
<button onClick={this.dlt_item.bind(this,i)}>Delete</button></div>
Related
So I'm practising react with a simple task master app, where I add each user input as a new task in an array of tasks. In the app, I have Add, Delete, and Update buttons.
Everything seems to be working fine except for the update function, it updates the last index of the array instead of the specific index I clicked.
Here is my JSX
const JsxElement = task.map((eachTask, index) => {
return (
<Fragment key={index}>
<div key={index} className="table-data-container">
<div className="item-data">{eachTask}</div>
<div className="item-data">{date}</div>
<div className="item-data">
<div className="btn-data-container">
<div className="btn-data">
<div className="btn" onClick={() => deleteTask(index)}>Delete</div>
</div>
<div className="btn-data">
<div className="btn" onClick={() => UpdateTaskBtn(eachTask, index)}>Update</div>
</div>
</div>
</div>
</div>
<br/>
{task.length - 1 === index &&
<div className="input-update-container">
<div className="input-area">
<input
ref={inputRef}
type="text"
/>
</div>
<div className="btn-update-add-container">
{update ?
<div className="btn-add" onClick={() => handleTaskUpdate(eachTask, index)}>Update
Task</div>
:
<div className="btn-add" onClick={handleTask}>Add Task</div>
}
</div>
</div>
}
</Fragment>
)
})
The first update button function prepares the input, sets the task to be updated and makes the update button visible. The second one is where I want the update action to happen once clicked.
function UpdateTaskBtn(eachTask) {
inputRef.current.value = eachTask
setUpdate(true)
}
function handleTaskUpdate(e, index) {
const list = [...task]
list[index] = inputRef.current.value
setTask(list)
inputRef.current.value = ""
setUpdate(false)
}
I want to be able to set the task to the specific index I want to update.
based on this line of code
{task.length - 1 === index &&
you are checking if the index is the last index , so you are passing the last index to the handleTaskUpdate function. so you can define a updateIndex state
const [updateIndex,setUpdateIndex] = useState()
then your function should look like this
function UpdateTaskBtn(eachTask,index) {
inputRef.current.value = eachTask
setUpdateIndex(index)
setUpdate(true)
}
function handleTaskUpdate(e, index) {
const list = [...task]
list[updateIndex] = inputRef.current.value
setTask(list)
inputRef.current.value = ""
setUpdate(false)
}
do not forget to pass index to UpdateTaskBtn function in onClick event
Try this
function handleTaskUpdate(e, index) {
const value = inputRef.current.value
const updatedTasks = task.map((task, i) => i === index ? value : task)
setTask(updatedTasks)
inputRef.current.value = ""
setUpdate(false)
}
Given a small quiz app, I'm trying to toggle a message under the questions to show the user that they have selected the correct answer or incorrect answer.
I have a small message that I'm gating with a boolean value which is set by the selection of the radio button (though the correct radio button isn't getting selected on initial click for some reason, only incorrect answers are), and need it to show a message of "You got it right" if the answer is true or "incorrect" if false. I can show true, but the logic isn't working to show false if the answer is incorrect and then clear the messaging when the "next question" button is clicked.
function App() {
let [points, setPoints] = useState(null);
let [counter, setCounter] = useState(null);
let [question, setQuestions] = useState();
let [isCorrect, setIsCorrect] = useState(false); <==Store correct answer selected
function Answer(props) {
return (
<li aria-labelledby="answers-list">
<label>
<input
type="radio"
name="answer_group"
className="answer"
value={props.answer}
onChange={checkAnswer}
/>
{props.answer}
</label>
</li>
);
}
function checkAnswer(e) {
let val = e.target.value;
let ans = question[counter].answers.filter((ans) => ans.value === val)[0];
displayCorrect(ans.correct);
//Toggles message to true if answer is correct
ans.correct === true ? setIsCorrect(true) : setIsCorrect(false);
}
function Quiz(props) {
return (
<div className="quiz">
<div className="quesiton" role="h2">
{props.question}
</div>
<ul className="answers">{props.children}</ul>
</div>
);
}
function displayCorrect(correct) {
let correct_msg = correct ? "correct" : "incorrect";
console.log("Answer was " + correct_msg);
}
function nextQuestion() {
setIsCorrect(false); <== Should hide message when user selects "next question" button
if (document.querySelector('input[name="answer_group"]:checked') == null) {
alert("Must select an answer before proceeding to the next question");
return;
}
let val = document.querySelector('input[name="answer_group"]:checked')
.value;
let answerObj = question[counter].answers.filter(
(ans) => ans.value === val
)[0];
let updated_points = answerObj.correct ? points + 1 : points;
setPoints(updated_points);
let nextQuestion = counter + 1;
if (counter < question.length - 1) {
setCounter(nextQuestion);
} else {
setCounter(0);
}
displayCorrect(answerObj.correct);
}
return (
<div className="Quiz slide-top">
{!is_started ? (
<div className="start-intro-wrapper">
<h1 className="name">Quiz App</h1>
<Starter start={start} />
</div>
) : (
<div className="quick-wrapper slide-in-bottom">
<Quiz question={question[counter].question}>
{question[counter].answers.map((answer, index, arr) => {
return (
<Answer
key={index}
index={index}
answer={answer.value}
correct={answer.correct}
/>
);
})}
</Quiz>
<div className="answer-controls">
{isCorrect === true ? <p>You got it right!</p> : null} <== Messaging should show if user has selected correct message if correct option is selected
<button onClick={(e) => nextQuestion()}>
Next question
</button>
</div>
</div>
)}
</div>
);
}
Codesandbox Link
It doesn't display anything because you put null in the other condition for the display.
If you replace it with {isCorrect === true ? <p>You got it right!</p> : <p>You got it wrong!</p>} the correct message is displayed.
You can also remove completly the function displayCorrect it's only writing in the console.
If you want to clear the message when the user click on "next question" you could do it with a new variable hasAnswered set at false by default.
You set it to true in your checkAnswer function, and to false in your nextQuestion function.
The code for the text at the bottom would then looks like:
{hasAnswered &&
(isCorrect === true ? <p>You got it right!</p> : <p>You got it wrong!</p>)
}
Regarding the issue with you needing to click twice to update the radio button selected, i think it's a re-render issue when isCorrect change.
To avoid the issue, you could store the value checked by the user and use this to display if the radio should be checked or no.
It works with the following changes
let [isChecked, setChecked] = useState(null);
[...]
function Answer(props) {
return (
<li aria-labelledby="answers-list">
<label>
<input
checked={isChecked===props.answer}
type="radio"
name="answer_group"
className="answer"
value={props.answer}
onChange={checkAnswer}
/>
{props.answer}
</label>
</li>
);
}
function checkAnswer(e) {
let val = e.target.value;
let ans = question[counter].answers.filter((ans) => ans.value === val)[0];
setIsCorrect(ans.correct);
setChecked(ans.value);
}
You also need setChecked(null) in your nextQuestion function to reset everything.
I am working on a project as a means to practice some stuff in react and I need to render a button for each of the map data. I did this successfully but expand and collapse has been giving me issue. Whenever I click on the button all data collapse and expand together.
const DataFetch = () => {
...
const [btnValue, setBtnValue] = useState('+');
const handleChange = (e) => {
setShowData(!showData);
setBtnValue(btnValue === '+' ? '-' : '+');
};
return (
<div className='container'>
...
{studentResults
.filter((val) => {
if (searchTerm === '') {
return val;
} else if (
val.firstName.toLowerCase().includes(searchTerm.toLowerCase()) ||
val.lastName.toLowerCase().includes(searchTerm.toLowerCase())
) {
return val;
} else {
return null;
}
})
.map((student) => {
return (
<div key={student.id}>
<div className='card'>
<div className='row'>
<div className='col-2'>
<div className='pic'>
<img src={student.pic} alt='avatar' />
</div>
</div>
<div className='col'>
<div className='details'>
<p className='name'>
{student.firstName.toUpperCase()}{' '}
{student.lastName.toUpperCase()}
</p>
<div className='sub-details'>
<p>Email: {student.email}</p>
<p>Company: {student.company}</p>
<p>Skill: {student.skill}</p>
<p>
Average:{' '}
{student.grades.reduce(
(a, b) => parseInt(a) + parseInt(b),
0
) /
student.grades.length +
'%'}
</p>
<button onClick={handleChange} className='showBtn'>
{btnValue}
</button>
{showData && (
<div>
<br />
{student.grades.map((grade, key) => {
return (
<p key={key}>
Test {key + 1}: {grade}%
</p>
);
})}
</div>
)}
...
Collapse Image
Expand Image
All the elements expand and collapse together because you assign to all of them the same state showData state.
One solution would be to add a new field to your data (so inside student) that is true or false when you want to expand or collapse the single student.
Another solution would be to create the showData state as an array where each element correspond to a different student. When you click the button, in this case, you pass to the function for example the id and with that you link your student to the right element inside the showData.
I'm having some issues updating a select tag value. When I click on it and try changing the value it logs the new value to the console, but it's value is not changing no matter how many times I click a different option. But when I make some changes in the code editor and save it it display the new value but if I try againg changing the value clicking on it it does not change.
const quantityChange = (e) => {
console.log('changing quantity')
const newCart = shoppingCart
console.log(
"new cart variable created. It's value is " + JSON.stringify(newCart)
)
const index = e.target.dataset.index
console.log('Item index is ' + index)
newCart[index]['quantity'] = e.target.value
console.log(
'The new quantity for the item is ' + newCart[index]['quantity']
)
setShoppingCart(newCart)
console.log(
'new value set for shopping cart. ' +
JSON.stringify(shoppingCart)
)
}
const ShoppingCart = ({ shoppingCart, quantityChange, removeFromCart }) => {
const onSubmit = (e) => {
e.preventDefault()
}
if (shoppingCart.length === 0) {
return <div>There's no items in the shopping cart</div>
}
const options = []
for (let i = 0; i <= 10; i++) {
options.push(
<option name="quantity-1" value={i} key={'qsfkajlf' + i}>
{i}
</option>
)
}
return (
<div>
<h1>
There's {shoppingCart.length} item{shoppingCart.length > 1 && 's'} in
your shopping cart.
</h1>
{shoppingCart.map((item, index) => {
const { id, name, price, image, quantity } = item
return (
<div key={id}>
<div className="flex-container">
<div className="img-container">
<img src={image} alt="" />
</div>
<div className="item-info">
<h2>{name}</h2>
<p>${price}</p>
</div>
<div className="remove-quantity">
<div className="quantity">
<form onSubmit={onSubmit}>
{/* TODO: don't allow more than 10 items */}
<select
id="quantity"
data-index={index}
onChange={quantityChange}
value={quantity}
>
{options}
</select>
</form>
</div>
<div className="remove-container">
<button data-remove={index} onClick={removeFromCart}>
x
</button>
</div>
</div>
</div>
</div>
)
})}
</div>
)
}
It isn't updating because you are doing this:
const quantityChange = (e) => {
console.log('changing quantity')
const newCart = shoppingCart // <-- copy a reference to shoppingCart
// do stuff
setShoppingCart(newCart) // <-- write the original (modified) object back in
}
As the object reference doesn't change, the re-render isn't triggered.
Instead, you just need to copy your object (instead of just copying the reference):
const quantityChange = (e) => {
console.log('changing quantity')
const newCart = {...shoppingCart} // <-- copy the contents into a new object
I am using react to produce a menu of options and currently I am only able to retrieve the last created menu option. Note that I am creating the options via looping, so this must be logic in my loop. Any advice will help.
var FilterMenu = React.createClass({
handleUserInput: function(filterText, selectedOption){
this.props.onUserInput(filterText, selectedOption);
},
render: function(){
return (
<div className="FilterMenu">
<FilterViews/>
<FilterItems
filterText={this.props.filterText}
selectedOptions={this.props.selectedOptions}
onUserInput={this.handleUserInput}
/>
</div>
)
}
});
var FilterViews = React.createClass({
render: function(){
return (<div className="FilterViews"></div>)
}
});
var FilterItems = React.createClass({
loadFiltersFromServer: function(){
ajaxServerRequest().then(fulfilled);
var self = this;
function fulfilled(response){
var filters = Object.keys(response[0]);
filters.length = 10;
self.setState({filters:filters});
}
},
getInitialState: function(){ //these are filters being loaded, not selected
return {filters:[]};
},
componentDidMount: function(){
this.loadFiltersFromServer();
},
handleChange: function(){
console.log('!!!145 - filter return',
this.refs.filterName.getDOMNode().innerText,
this.refs.filterOptionsInput.getDOMNode().value,
this.refs.filterTextInput.getDOMNode().value);
this.props.onUserInput(
this.refs.filterTextInput.getDOMNode().value,
this.refs.filterOptionsInput.getDOMNode().value
);
},
render: function(){
var self = this;
//console.log('FilterItems.this.props',this.props);
//var Cost = [].push(<option>{filter.slice(5,filter.length)}</option>);
var Cost = AppartmentCostRange.map(function(cost,index){
return( <option value={cost} ref="filterOptionsInput" key={index}>
{cost}
</option>)
});
var FilterItems = this.state.filters.map(function(filter, index){
return (
<div>
<span value={filter} ref="filterName" key={index}>{filter}</span>
<select>
{Cost}
</select>
</div>
)
});
return (
<div className="FilterItems">
<h3>Filter Items</h3>
Quick Search
<input
type="text"
placeholder="search.."
value={this.props.filterText}
ref="filterTextInput"
onChange={this.handleChange}
/>
<div onChange={this.handleChange}>
{FilterItems}
</div>
</div>
)
}
});
I think this component is trying to do too much. Split it up
FilteredList
ListItem
CostSelector
you can generate the cost map data once and pass it to the CostSelector that each ListItem will have attached.
Currently you're passing one set of {Costs} to each options and react thinks it's just the one set of options. Wrap the whole select in a component and just pass the properties to it.