Develop Reference

I have input a unique "key" prop but still got error asking me to input it in React

so this is my render, it render basically a ui where a username and their email. it also have the option to add new user but when I run the code in my local host, i get this error in my console: Warning: Each child in a list should have a unique "key" prop.
render() {
return (
<div className="App">
{this.state.users.map((user) => {
return (
<React.Fragment>
<div key={user._id} className="box">
<h3>{user.name}</h3>
<h4>{user.email}</h4>
<button
onClick={() => {
this.beginEdit(user);
}}
>
Update
</button>
<button
onClick={() => {
this.deleteUser(user);
}}
>
Delete
</button>
</div>
</React.Fragment>
);
})}
{this.renderAddUser()}
</div>
);
}
}
this is my AddRenderUser
// render new User
renderAddUser() {
return (
<React.Fragment >
<input
type="text"
placeholder="User name"
value={this.state.newUserName}
onChange={this.updateFormField}
name="newUserName"
/>
<input
type="text"
placeholder="User email"
value={this.state.newUserEmail}
onChange={this.updateFormField}
name="newUserEmail"
/>
<button onClick={this.addUser}>Add</button>
</React.Fragment>
);
}
Although I did put the keys props in my div, so not sure how to correct this error

Your key should be in your top-most element
render() {
return (
<div className="App">
{this.state.users.map((user) => {
return (
<React.Fragment key={user._id}>
<div className="box">
<h3>{user.name}</h3>
<h4>{user.email}</h4>
<button
onClick={() => {
this.beginEdit(user);
}}
>
Update
</button>
<button
onClick={() => {
this.deleteUser(user);
}}
>
Delete
</button>
</div>
</React.Fragment>
);
})}
{this.renderAddUser()}
</div>
);
}
}

You need to add the key prop to the React.Fragment tag like this:
<React.Fragment key={user._id}>
Or please try to use index value instead of user.id as follows:
render() {
return (
<div className="App">
{this.state.users.map((user, i) => {
return (
<React.Fragment key={i}>
<div className="box">
<h3>{user.name}</h3>
<h4>{user.email}</h4>
<button
onClick={() => {
this.beginEdit(user);
}}
>
Update
</button>
<button
onClick={() => {
this.deleteUser(user);
}}
>
Delete
</button>
</div>
</React.Fragment>
);
})}
{this.renderAddUser()}
</div>
);
}

React, conditional rendering inside map method

I have the following code and I want to apply a conditional rendering, because the index 0 does not exist. I don't want to render the information for this particular index. How can I do it?
return (
<section>
{pokemonCards.map((pokemon, index) =>
<div key={index}>
<img
src={`https://raw.githubusercontent.com/PokeAPI/sprites/master/sprites/pokemon/${index}.png`}
alt={pokemon.name}/>
<p>{pokemon.name}</p>
</div>
)}
<button
className="get-more-button"
onClick={getMorePokemons}>Get more pokemons
</button>
</section>
)

This should work:
return (
<section>
{pokemonCards.map((pokemon, index) =>
{index === 0 ? null : <div key={index}>
<img
src={`https://raw.githubusercontent.com/PokeAPI/sprites/master/sprites/pokemon/${index}.png`}
alt={pokemon.name}/>
<p>{pokemon.name}</p>
</div>
)}
<button
className="get-more-button"
onClick={getMorePokemons}>Get more pokemons
</button>}
</section>
)

You could do as below if you do not want to render an empty div for the nonexisting pokemon:
return (
<section>
{pokemonCards.map(
(pokemon, index) =>
index !== 0 && (
<div key={index}>
<img
src={`https://raw.githubusercontent.com/PokeAPI/sprites/master/sprites/pokemon/${index}.png`}
alt={pokemon.name}
/>
<p>{pokemon.name}</p>
</div>
)
)}
<button className="get-more-button" onClick={getMorePokemons}>
Get more pokemons
</button>
</section>
);

React change icon onClick from loop

I included an Icon while mapping an array and I need to change the icon on that specific iteration onclick, I also want to render the test results when the icon is clicked.
I'm not sure how to get a unique value that is specific to this iteration that will handle this change or is my structure all wrong?
** went to sleep found solution = encapsulation **
map the component so the boolean variable is local scoped to that iteration.
shared solution below
const Students = ({students}) => {
const [showTests, setShowTests] = useState(false);
return (
<div className="wrapper" key={student.id}>
<div className="img-container">
<img src={student.pic} alt="student" />
</div>
<div className="content">
<h1>
{student.firstName.toUpperCase()} {student.lastName.toUpperCase()}
</h1>
<p>Email: {student.email}</p>
<p>Company: {student.company}</p>
<p>Skill: {student.skill}</p>
<p>Average: {averageGrade(student.grades)}%</p>
{showTests && <TestResults results={student.tests} />}
</div>
{showTests ? (
<FontAwesomeIcon
onClick={() => setShowTests(!showTests)}
className="faIcon"
icon={faMinus}
/>
) : (
<FontAwesomeIcon
onClick={() => setShowTests(!showTests)}
className="faIcon"
icon={faPlus}
/>
)}
</div>
);
}
const Main = () => {
return (
<div className="main" id="main">
{filteredStudents.map(student => (
//each iteration is a unique component
<Students student={student} />
))}
</div>
);
}
<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>
Thanks ahead of time for any suggestions

The return must always have a top-level tag.
const Students = ({ students }) => {
return (
<>
{students.map((student, i) => (
<div className="wrapper" key={student.id}>
<div className="img-container">
<img src={student.pic} alt="student" />
</div>
<div className="content">
<h1>
{student.firstName.toUpperCase()}{" "}
{student.lastName.toUpperCase()}
</h1>
<p>Email: {student.email}</p>
<p>Company: {student.company}</p>
<p>Skill: {student.skill}</p>
<p>Average: {averageGrade(student.grades)}%</p>
{faMinus && <TestResults results={student.tests} />}
</div>
<FontAwesomeIcon
id={i}
onClick={(e) => handleTests(e.target.id)}
className="faIcon"
icon={current ? faPlus : faMinus}
/>
</div>
))}
</>
);
};

Let me know if this is what you're thinking. Just store the index in a state variable and compare against it. When they click change the index to the one they clicked on.
const Students = ({students}) => {
const [selectedIndex, setSelectedIndex] = useState(0)
function handleTests(id, index) { //NEW
//Your current code
setSelectedIndex(index) //NEW
}
return (
{students.map((student, i) => (
<div className="wrapper" key={student.id}>
<div className="img-container">
<img src={student.pic} alt="student" />
</div>
<div className="content">
<h1>
{student.firstName.toUpperCase()} {student.lastName.toUpperCase()}
</h1>
<p>Email: {student.email}</p>
<p>Company: {student.company}</p>
<p>Skill: {student.skill}</p>
<p>Average: {averageGrade(student.grades)}%</p>
{selectedIndex == i && <TestResults results={student.tests} />} //NEW
</div>
<FontAwesomeIcon
id={i}
onClick={e => handleTests(e.target.id, i)} //NEW
className="faIcon"
icon={selectedIndex == i ? faPlus : faMinus}
/>
</div>
))}
)
}

Are nested conditional renderings possible with REACT?

I am trying to achieve the following for a special page
const Pricing = () => {
return (
<main class="o-main">
<section class="plan">
<div class="plan">
<div class="plan">
<h1 class="plan">Select the best plan</h1>
<p class="plan">from plan1 to plan3</p>
</div>
</div>
</section>
<div class="plan">
<div class="plan">
<h1 class="plan">features</h1>
<p class="plan">features of plan1</p>
</div>
</div>
{isLoggedin() ? (
{userPlan() === 'plan1' ? (
<FaCheckCircle />
<a class="plan">current plan</a>
) : (
<a class="plan" onClick={() => {...}}>sign up</a>
)}
) : (
sign up
)}
<div class="plan">
<div class="plan">
<h1 class="plan">features</h1>
<p class="plan">features of plan2</p>
</div>
</div>
{isLoggedin() ? (
<>
{userPlan() === 'plan2' ? (
<>
<FaCheckCircle />
<a class="plan">current plan</a>
</>
) : (
<>
<a class="plan" onClick={() => {...}}>upgrade to plan2</a>
</>
)}
</>
) : (
<>
sign up
</>
)}
<div class="plan">
<div class="plan">
<h1 class="plan">features</h1>
<p class="plan">features of plan3</p>
</div>
</div>
{isLoggedin() ? (
<>
{userPlan() === 'plan3' ? (
<>
<FaCheckCircle />
<a class="plan">current plan</a>
</>
) : (
<>
<a class="plan" onClick={() => {...}}>upgrade to plan3</a>
</>
)}
</>
) : (
<>
sign up
</>
)}
</main>
);
};
export default Pricing;
userPlan() is a function of fetch API call that returns a string like plan1 or plan2
but i am getting the following error
Syntax error: Unexpected token
{userPlan() === 'plan1' ? (
^
anything am missing or the logic is not possible in react?

before using this function's return value , check if it is available:
isLoggedin() && userPlan() ? ...

issue was that here is what is what i really had
{isLoggedin() ? (
{userPlan() === 'plan1' ? (
<FaCheckCircle />
<a class="plan">current plan</a>
) : (
<a class="plan" onClick={() => {...}}>sign up</a>
)}
) : (
sign up
)}
and here is what worked and removed the syntax error
{isLoggedin() ? (
<>
{userPlan() === 'plan1' ? (
<>
<FaCheckCircle />
<a class="plan">current plan</a>
</>
) : (
<>
<a class="plan" onClick={() => {...}}>sign up</a>
</>
)}
</>
) : (
<>
sign up
</>
)}
the thing is sometimes it does not complain about the <> and </> and sometimes it does, in this case
anyone that knows why this is inconsistent, please comment below

Modal dialog displays from all elements of mapped array. How to select each item by ts and react js?

This code:
How to display a dialog when a button is clicked using react and typescript?
I wanna open dialog from each todos, how to make it ? I used react js and typescript. Help me to resolve this problem.
interface ListProps {
todos: INote[];
onDelete: (title: string) => void;
}
const TodoList: React.FunctionComponent<ListProps> = ({ todos, onDelete }) => {
const [showAlert, setShowAlert] = useState(false);
const [todo, setTodos] = useState(null);
How to select each item by ts?It doesn't work. What is reason? Thanks!
const handleOpenDialog = (todos: any) => {
setTodos(todos);
setShowAlert(true);
};
const handleCloseDialog = () => {
setShowAlert(false);
};
return (
<>
<section className="list list--wrapper">
{todos.map((todos) => (
<div className="item list__item" key={todos.title}>
<span className="item__title">{todos.title}</span>
<div className="item__group">
<input
className="item__completed"
type="checkbox"
checked={todos.completed}
/>
<span className="item__decs">{todos.desc}</span>
</div>
<div className="item__btn">
<button
className="item__btnd"
onClick={() => handleOpenDialog(todos)}
>
Delete
</button>
<button className="item__btne">Edit</button>
</div>
{showAlert && todo && (
<AlertDialog
handleCloseDialog={handleCloseDialog}
title={todos.title}
/>
)}
</div>
))}
</section>
</>
);
};
export default TodoList;

just add a condition to only show the AlertDialog on selected todos
<section className="list list--wrapper">
{todos.map((todos) => (
<div className="item list__item" key={todos.title}>
<span className="item__title">{todos.title}</span>
<div className="item__group">
<input
className="item__completed"
type="checkbox"
checked={todos.completed}
/>
<span className="item__decs">{todos.desc}</span>
</div>
<div className="item__btn">
<button
className="item__btnd"
onClick={() => handleOpenDialog(todos)}
>
Delete
</button>
<button className="item__btne">Edit</button>
</div>
{showAlert && todos.title===todo?.title && (
<AlertDialog
handleCloseDialog={handleCloseDialog}
title={todos.title}
/>
)}
</div>
))}
</section>
or just move the AlertDialog outside the map
<section className="list list--wrapper">
{todos.map((todos) => (
<div className="item list__item" key={todos.title}>
<span className="item__title">{todos.title}</span>
<div className="item__group">
<input
className="item__completed"
type="checkbox"
checked={todos.completed}
/>
<span className="item__decs">{todos.desc}</span>
</div>
<div className="item__btn">
<button
className="item__btnd"
onClick={() => handleOpenDialog(todos)}
>
Delete
</button>
<button className="item__btne">Edit</button>
</div>
</div>
))}
{showAlert && todo && (
<AlertDialog
handleCloseDialog={handleCloseDialog}
title={todos.title}
/>
)}
</section>