I am new to react however I have done this same(ish) thing multiple times, however, this time it is just not working - I am assuming there is something I am fundamentaily not understanding. Please help!
I have a good old table:
<table>
<thead>
<tr>
<th>Name</th>
<th>Email</th>
</tr>
</thead>
<tbody>
<TableRowUser key={1} />
<TableRowUser key={2} />
<TableRowUser key={3} />
</tbody>
</table>
And a row:
import React from 'react';
const TableRowUser = () => {
return <tr>
<td>TEST</td>
<td>TEST</td>
</tr>;
};
export default TableRowUser;
This works just as expected.
However, when I change from hard code to using a map - nothing is rendered:
...
<tbody>
{users.map(user => {
console.log(user.name);
<TableRowUser key={user.id} />
})}
</tbody>
...
I should note - my data is fine as this console log prints correctly.
Just no TableRowUser is returned.
This appears trivial - What am I missing?
The issue you are running into is how arrow functions work.
You can do:
() => value
for a quick way to return a value, but if you are putting a body on the code, you need to use the return keyword
() => { return value }
Thus, your code should be:
<tbody>
{users.map(user => {
console.log(user.name);
return <TableRowUser key={user.id} />
})}
</tbody>
or just
<tbody>
{users.map(user => <TableRowUser key={user.id} />)}
</tbody>
Related
I am facing a weird problem while working with tankStack react-table. I want render some specific tags with extra data. example: i want to render the age column like this (this is the {age})
But don't want to make the tag child of tag but that is happening
Here is my code
<table>
<thead>
{table.getHeaderGroups().map((headerGroup) => (
<tr key={headerGroup.id}>
{headerGroup.headers.map((header) => (
<th key={header.id}>
{header.isPlaceholder
? null
: flexRender(
header.column.columnDef.header,
header.getContext()
)}
</th>
))}
</tr>
))}
</thead>
<tbody>
{table.getRowModel().rows.map((row) => (
<tr key={row.id}>
{row.getVisibleCells().map((cell) => {
return(
<td key={cell.id}>
{flexRender(
cell.column.columnDef.cell,
cell.getContext()
)}
</td>
)
})
}
</tr>
))}
</tbody>
</table>
Column.js
export const COLUMNS = [
{
header:'First Name',
accessorKey:'first_name',
id:'first_name'
},
{
header:'Last Name',
accessorKey:'last_name',
id:'last_name'
},
{
header:'Age',
accessorKey:'age',
id:'age',
cell: data => <td>this is age{data.getValue()}</td>,
enableGlobalFilter: false,
}
]
I have a functional component which is reading data from an API. I have defined an Interface but unable to loop and display in table using Map in react.
error
index.js:1 Warning: Each child in a list should have a unique "key" prop.
Interface
export interface ISiteManager{
managerId: number,
name: string,
isDeleted: false
}
React functional component return template
...
return (
<div>
<h2>EziTracker Dashboard Report</h2>
{eziStatusCollection && eziStatusCollection.length >0 && (
<table className="table">
<thead>
<tr>
<th>ManagerId</th>
<th>Name</th>
<th>Is Deleted</th>
</tr>
</thead>
{
eziStatusCollection.map((item, index) => {
return(
<tbody>
<tr key={index}>
<td>{item.managerId}</td>
<td>{item.name}</td>
<td>{item.isDeleted}</td>
</tr>
</tbody>
)})
}
</table>)}
</div>
);
};
export default MyComponent;
Your table body should be outside the map, as it's looping it each time as well:
<tbody>
{
eziStatusCollection.map((item, index) => {
return(
<tr key={index}>
<td>{item.managerId}</td>
<td>{item.name}</td>
<td>{item.isDeleted}</td>
</tr>
)})
}
</tbody>
This way the map key will be associated with each child (tr) and the error shouldn't occur.
Why in the following code Delete button click does not hit the delete method? What i am missing important thing? I am new to learn React.js
delete(e) {
console.log('Deleted');
}
static renderCatTable(Categories) {
return (
<table className='table table-striped'>
<thead>
<tr>
<th>Code</th>
<th></th>
</tr>
</thead>
<tbody>
{Categories.map(category =>
<tr key={category._id}>
<td>{category.code}</td>
<td><button onClick={this.delete} className="btn btn-danger">Delete</button></td>
</tr>
)}
</tbody>
</table>
);
}
I have defined the binding inside the constructor
this.delete = this.delete.bind(this);
The render function is given below.
render() {
let contents = this.state.loading
? <p><em>Loading...</em></p>
: Category.renderCatTable(this.state.Categories);
return (
<div>
{contents}
</div>
);
}
Because that render method is static. By definition, static methods cannot access an instance variable. You should remove that modifier if possible and it should work.
I want to generate a row for each item in my list. The way i'm currently trying to achieve this is with the following:
<thead>
<tr>
<th>Title</th>
<th>Date</th>
<th>People</th>
<th>Status</th>
</tr>
</thead>
{ this.renderEvents() }
renderEvents() {
const events = this.state.data;
console.log(events);
return (
<tbody>
{ events.forEach((event) => {
return (
<tr>
<td>{event.title}</td>
<td>{event.startDate}</td>
<td>{event.userList.length}</td>
<td><Badge color="success">Coming</Badge></td>
</tr>
);
})}
</tbody>
);
}
The problem i'm currently facing is that my console.log(events) line gets executed twice and the table stays empty.
Any help is appreciated! :)
Array#forEach does not return a new array. Try Array#map instead!
return (
<tbody>
{ events.map((event) => {
return (
<tr>
<td>{event.title}</td>
<td>{event.startDate}</td>
<td>{event.userList.length}</td>
<td><Badge color="success">Coming</Badge></td>
</tr>
);
})}
</tbody>
);
Another way to do this
render(){
const data = events.map(
event => {
<tbody>
<tr>
<td>{event.title}</td>
<td>{event.startDate}</td>
<td>{event.userList.length}</td>
<td><Badge color="success">Coming</Badge></td>
</tr>
</tbody>
})
return (
<div>
{data}
</div>
)
}
More React idiomatic solution would be to use a React Component instead of calling function that returns jsx. Component is created once and mounted once, instead, function will each time return a new component (meaning the memory link will change) that will cause React reconciliation mechanism to each time mount and unmount a Component. That is not good for React performance.
I would recommend structuring your code in a next manner:
class EventViewer extends React.Component {
// keep logic of fetching events here and saving them (to state for example)
render() {
return (
<table>
<EventVieverHeader />
<EventVieverBody events={this.state.events}/>
</table>
)
}
}
const EventVieverHeader = () => (
<tr>
<td>{event.title}</td>
<td>{event.startDate}</td>
<td>{event.userList.length}</td>
<td><Badge color="success">Coming</Badge></td>
</tr>
);
const EventVieverBody = ({events}) => (
<tbody>
{events.map(
event => {
<tr>
<td>{event.title}</td>
<td>{event.startDate}</td>
<td>{event.userList.length}</td>
<td><Badge color="success">Coming</Badge></td>
</tr>
})}
</tbody>
)
I am trying to get a click even to work with a table in reactjs. My first attempt was to make the whole row clickable. Here is my code:
var UserList = React.createClass({
getInitialState: function() {
return getUsers();
},
handleClick: function(e) {
console.log("clicked");
},
render: function() {
var users = this.state.users.map(function(user) {
return (
<tr onClick={this.handleClick}>
<td>{user.name}</td>
<td>{user.age}</td>
<td></td>
</tr>
);
});
return(
<div className="container">
<table className="table table-striped">
<thead>
<tr>
<th>Name</th>
<th>Age</th>
<th>Full Detail</th>
</tr>
</thead>
<tbody>
{users}
</tbody>
</table>
</div>
);
}
});
This did not work. I then tried to add a button in the table:
<button className="btn" onClick={this.handleClick}>Full Detail</button>
That also did not work. I have other onClick's working throughout my app, but how do I make this work with a table?
Your problem is the function of user that creates the table row is not bound to your react component. The value of this will not be your react component and handleClick will not exist as a property of this.
Try
var users = this.state.users.map(function(user) {
return (
<tr onClick={this.handleClick}>
<td>{user.name}</td>
<td>{user.age}</td>
<td></td>
</tr>
);}.bind(this);
});
Or use Underscore's bind if you want it to work on all browsers.
I'm new to react. How about this? You just wrap it in another function, then that function holds the closure scope and it calls it correctly.
No idea if this is bad practice or the performance difference, but it seems to work...
var users = this.state.users.map(function(user) {
return (
<tr onClick={()=>this.handleClick(user)}>
<td>{user.name}</td>
<td>{user.age}</td>
<td></td>
</tr>
);}.bind(this);
});
Binding creates a new object. Thus if you bind your function for N employees, you are inefficiently creating N new functions. A more elegant approach is to bind the function once, and pass a reference to every row. Your original code was quite close. This is what I would suggest:
handleClick = e => {
const user = this.state.users.find(u => u.uuid == e.target.dataset.uui)
console.log("clicked");
},
render() {
return(
<div className="container">
<table className="table table-striped">
<thead>
<tr>
<th>Name</th>
<th>Age</th>
<th>Full Detail</th>
</tr>
</thead>
<tbody>
{this.state.users.map(user =>
(
<tr data-uuid={user.uuid} onClick={this.handleClick}>
<td>{user.name}</td>
<td>{user.age}</td>
<td>{user.details || ''}</td>
</tr>
)
)}
</tbody>
</table>
</div>
);
}
});