"Toggle undifined" message when click button in React.js - reactjs

I am newbie in React js, and I have made a toggle class button in Reactjs.
But When I clicked i got error message.
TypeError : Cannot read property 'toggle' of undefined
This is my code below.
What is wrong with my code? please help.
import React from 'react'
export default function About() {
const navRef = React.useRef(null);
const btnRef = React.useRef(null);
const onToggleClick = () => {
navRef.current.classList.toggle("show");
btnRef.current.classList.toggle("active");
};
return (
<>
<button onClick={onToggleClick} ref={btnRef}>Toggle</button>
<nav ref={navRef}>Navigation menu</nav>
</>
);
}

In react, you can learn to toggle by using state.
In the following example, we set a toggle state show, and toggle it true/false.
We will then set the className with the appropriate css class we want it to have.
import React, { useState, useEffect } from 'react'
export default function About() {
const [ show, setShow ] = useState(false) //default to hide
useEffect(() => {
if (show) {
document.body.classList.add('bodyclass');
} else {
document.body.classList.remove('bodyclass');
}
}, [show])
const onToggleClick = () => setShow(!show) //if it's true, set to false. vice-versa
return (
<>
<button onClick={onToggleClick} className={ show ? 'active' : ''}>Toggle</button>
<nav className={ show ? 'show' : ''}>Navigation menu</nav>
</>
);
}

Related

onClick to open menu conflicting with useClickOutside custom hook in React

I am trying to implement a custom hook to close my nav menu with any click outside of it following this tutorial - https://www.youtube.com/watch?v=XEQ9nEHYIbw&list=PLZlA0Gpn_vH-aEDXnaFNLsqiJWFpIWV03&index=5&t=119s
However it is not working and I can't understand why it's behaving differently.
I have a button with an onClick function to open the menu. I want the custom hook to close the menu on any click outside it. However when I click the menu button to open the menu, the click events are conflicting - the menu state changes to open and then the custom hook runs as well and closes it again.
I have resolved the issue by passing a ref to the button to the hook as well - but is there a better way? Why is this behaving differently to the tutorial where that isn't required?
import "./styles.css";
import { useRef, useState } from "react"
import useClickOutside from "./useClickOutside"
export default function App() {
const [open, setOpen] = useState(false)
const navRef = useRef()
console.log(open)
useClickOutside(navRef, () => {
if (open) setOpen(false);
});
return (
<div className="App">
<header>
<div className="container">
<h1>Logo</h1>
<button onClick={() => setOpen(true)}>{open ? "X" : "Menu"}</button>
</div>
<nav ref={navRef} className={open ? "" : "hide"}>
Home
About
</nav>
</header>
<h1>Main content..</h1>
</div>
);
// useClickOutside.js
import useEventListener from "./useEventListener"
export default function useClickOutside(ref, cb) {
useEventListener(
"click",
(e) => {
if (ref.current == null || ref.current.contains(e.target)) return;
cb(e);
},
document
);
}
// useEventListener.js
import { useEffect, useRef } from "react";
export default function useEventListener(eventType, callback, element = window) {
const callbackRef = useRef(callback);
useEffect(() => {
callbackRef.current = callback;
}, [callback]);
useEffect(() => {
const handler = (e) => callbackRef.current(e);
element.addEventListener(eventType, handler);
return () => element.removeEventListener(eventType, handler);
}, [eventType, element]);
}

In react, how can I deselect an element after it has been set as active with onClick?

I have an image grid in react, with an onclick function that highlights the selected image. Clicking another image will change the active element but I'd like to be able to re-click the selected icon to deselect it and return the grid to default.
Here is my codesandbox and the script is below
import { useState, useRef, useEffect } from "react";
import "./App.css";
import { Data } from "./Data.js";
function App() {
const scrollRef = useRef();
useEffect(() => {
const el = scrollRef.current;
if (el) {
const wheelListener = (e) => {
e.preventDefault();
el.scrollTo({
left: el.scrollLeft + e.deltaY * 5,
behavior: "smooth"
});
};
el.addEventListener("wheel", wheelListener);
return () => el.removeEventListener("wheel", wheelListener);
}
}, []);
const [active, setActive] = useState(-1);
const [active2, setActive2] = useState(false);
return (
<div ref={scrollRef} className="grid_container">
{Data.map((prev, i) => {
return (
<div
onClick={() => {
setActive(i);
setActive2(true);
console.log(prev.Team);
}}
className={`${
(active === i && "scale") || (active2 && "notScale")
} card`}
key={i}
>
<img src={prev.TeamBadge} alt="" />
</div>
);
})}
</div>
);
}
export default App;
If I understand the problem correctly, I think this solves the problem, based on the codesandbox:
onClick={() => {
setActive(i);
if (active === i) {
setActive2(null);
setActive(null);
} else {
setActive2(true);
}
console.log(i);
console.log(prev.Team);
}}
since every team has its unique number, the logic here is to check if the same number is in the state (if that makes sense). Let me know if this was you are looking for!
You can set your state like that :
setActive2(!active2);

Ternary condition on onclick event

I am trying to create a to-do application in React. Code I have so far adds to-do items to the to-do list. When I click on the edit icon I had put turnery condition for the done icon but it's not working. Can someone explain what is wrong with my code?
App.js
import './App.css';
import React, { useState } from 'react';
import TodoList from './TodoList';
import { v4 as uuidv4 } from 'uuid';
function App() {
// const [input, setInput] = useState('');
const [todos, setTodo] = useState([]);
const input = React.useRef();
const addTodo = (e) => {
e.preventDefault();
const id = uuidv4();
setTodo([...todos, { id: id, text: input.current.value }])
input.current.value='';
}
const deleteTodo = (id) => {
setTodo(todos.filter(todo => todo.id !== id));
}
const editTodo = (id) => {
}
return (
<div className="App">
<form>
<input type="text" ref={input}/>
<button type="submit" onClick={addTodo}>Enter</button>
</form>
<TodoList todos={todos} deleteTodo={deleteTodo} editTodo={editTodo}/>
</div>
);
}
export default App;
TodoItem.js
import React from 'react'
import DeleteIcon from '#material-ui/icons/Delete';
import EditIcon from '#material-ui/icons/Edit';
import CheckBoxOutlineBlankIcon from '#material-ui/icons/CheckBoxOutlineBlank';
import DoneIcon from '#material-ui/icons/Done';
const TodoItem = ({todo, deleteTodo, editTodo}) => {
return (
<>
<div>
<CheckBoxOutlineBlankIcon/>
<input type="text" value={todo.text} readOnly={true}/>
</div>
<div>
{ <EditIcon/> ? <EditIcon onClick={editTodo}/> : <DoneIcon/> }
<DeleteIcon onClick={deleteTodo}/>
</div>
</>
)
}
export default TodoItem
There are a few problems with your code. One, also pointed out by Abu Sufian is that your ternary operator will always trigger whatever is immediately after ?, because <EditIcon/> is just a component and will always be true.
But more fundamentally, to do what you want, you will need to add another properly to your todo list, say, status. So when a task goes in for the first time, it will be in pending status, then once you click your Edit icon, it will change to done. And that's how we will toggle that icon with a ternary operator.
So I would change your addTodo function to
const addTodo = (e) => {
e.preventDefault();
const id = uuidv4();
setTodo([
...todos,
{ id: id, text: input.current.value, status: "pending" }
]);
input.current.value = "";
};
Then I would change your editTodo to:
const editTodo = (id) => {
console.log(id);
setTodo(
todos.map((todo) => {
if (todo.id === id) todo.status = "done";
return todo;
})
);
};
And finally, I would change your ternary part to:
{todo.status === "pending" ? (
<EditIcon onClick={() => editTodo(todo.id)} />
) : (
<DoneIcon />
)}
Here is a complete Sandbox for you. Sorry I don't have your CSS so I can't make it look super pretty.
Maybe you are looking for something like this.
{ !todo.done ? <EditIcon onClick={editTodo}/> : <DoneIcon/> }
I believe checking whether a todo item is done or not should happen with a property of todo object itself.
In a ternary you need to start with a condition.
condition ? do something when true : do something when false
So you have to have a condition in the first place. In your case EditIcon is not a condition.
If you are looking for a way to mark a todo as completed so you need to do more things.
const markAsCompleted = id => {
const todo = todos.find(todo => todo.id !== id);
setTodo([...todos, {...todo, done: true }]);
}
Then you can decide based on whether a todo is done or not.

React scroll start from bottom

I have a chat page where I get a message from the server, I need to implement it so that the scroll of the starts from the last element. I use the useRef hook for scrolling, but my console gives an error (TypeError: Cannot read property 'scrollIntoView' of null). but everything works correctly in the sandbox. I can not understand where is my mistake.
codesandbox
React:
import React, {useEffect, useRef} from "react";
import styled from "styled-components";
const TabPanelBody = ({messages}) => {
const messagesEndRef = useRef(null);
const scrollToBottom = () => {
messagesEndRef.current.scrollIntoView({ behavior: "smooth" });
};
useEffect(scrollToBottom, []);
return (
<TabBody>
{
messages.messages ? messages.messages.map((data, index) => {
return (
<Messages key={index} className={ data.my ? 'send-messages' : 'incoming-messages' }>
{data.message}
<div ref={messagesEndRef} />
</Messages>
)
}) : null
}
</TabBody>
);
};
Error
Check if there is a Current value
The error states that messagesEndRef.current is null. So make sure that there's a value inside the current before trying to run the function scrollIntoView.
messagesEndRef.current && messagesEndRef.current.scrollIntoView({ behavior: "smooth" });
The ref isn't set yet when the useEffect is called. You have to check if the ref is set and then call the function.
import React, {useEffect, useRef} from "react";
import styled from "styled-components";
const TabPanelBody = ({messages}) => {
const messagesEndRef = useRef(null);
useEffect(() => {
messagesEndRef.current?.scrollIntoView({ behavior: "smooth" });
}, [messagesEndRef.current]);
return (
<TabBody>
{
messages.messages ? messages.messages.map((data, index) => {
return (
<Messages key={index} className={ data.my ? 'send-messages' : 'incoming-messages' }>
{data.message}
<div ref={messagesEndRef} />
</Messages>
)
}) : null
}
</TabBody>
);
};

Can a React portal be used in a Stateless Functional Component (SFC)?

I have used ReactDOM.createPortal inside the render method of a stateful component like so:
class MyComponent extends Component {
...
render() {
return (
<Wrapper>
{ReactDOM.createPortal(<FOO />, 'dom-location')}
</Wrapper>
)
}
}
... but can it also be used by a stateless (functional) component?
Will chime in with an option where you dont want to manually update your index.html and add extra markup, this snippet will dynamically create a div for you, then insert the children.
export const Portal = ({ children, className = 'root-portal', el = 'div' }) => {
const [container] = React.useState(() => {
// This will be executed only on the initial render
// https://reactjs.org/docs/hooks-reference.html#lazy-initial-state
return document.createElement(el);
});
React.useEffect(() => {
container.classList.add(className)
document.body.appendChild(container)
return () => {
document.body.removeChild(container)
}
}, [])
return ReactDOM.createPortal(children, container)
}
It can be done like this for a fixed component:
const MyComponent = () => ReactDOM.createPortal(<FOO/>, 'dom-location')
or, to make the function more flexible, by passing a component prop:
const MyComponent = ({ component }) => ReactDOM.createPortal(component, 'dom-location')
can it also be used by a stateless (functional) component
?
yes.
const Modal = (props) => {
const modalRoot = document.getElementById('myEle');
return ReactDOM.createPortal(props.children, modalRoot,);
}
Inside render :
render() {
const modal = this.state.showModal ? (
<Modal>
<Hello/>
</Modal>
) : null;
return (
<div>
<div id="myEle">
</div>
</div>
);
}
Working codesandbox#demo
TSX version based on #Samuel's answer (React 17, TS 4.1):
// portal.tsx
import * as React from 'react'
import * as ReactDOM from 'react-dom'
interface IProps {
className? : string
el? : string
children : React.ReactNode
}
/**
* React portal based on https://stackoverflow.com/a/59154364
* #param children Child elements
* #param className CSS classname
* #param el HTML element to create. default: div
*/
const Portal : React.FC<IProps> = ( { children, className, el = 'div' } : IProps ) => {
const [container] = React.useState(document.createElement(el))
if ( className )
container.classList.add(className)
React.useEffect(() => {
document.body.appendChild(container)
return () => {
document.body.removeChild(container)
}
}, [])
return ReactDOM.createPortal(children, container)
}
export default Portal
IMPORTANT useRef/useState to prevent bugs
It's important that you use useState or useRef to store the element you created via document.createElement because otherwise it gets recreated on every re-render
//This div with id of "overlay-portal" needs to be added to your index.html or for next.js _document.tsx
const modalRoot = document.getElementById("overlay-portal")!;
//we use useRef here to only initialize el once and not recreate it on every rerender, which would cause bugs
const el = useRef(document.createElement("div"));
useEffect(() => {
modalRoot.appendChild(el.current);
return () => {
modalRoot.removeChild(el.current);
};
}, []);
return ReactDOM.createPortal(
<div
onClick={onOutSideClick}
ref={overlayRef}
className={classes.overlay}
>
<div ref={imageRowRef} className={classes.fullScreenImageRow}>
{renderImages()}
</div>
<button onClick={onClose} className={classes.closeButton}>
<Image width={25} height={25} src="/app/close-white.svg" />
</button>
</div>,
el.current
);
Yes, according to docs the main requirements are:
The first argument (child) is any renderable React child, such as an element, string, or fragment. The second argument (container) is a DOM element.
In case of stateless component you can pass element via props and render it via portal.
Hope it will helps.
Portal with SSR (NextJS)
If you are trying to use any of the above with SSR (for example NextJS) you may run into difficulty.
The following should get you what you need. This methods allows for passing in an id/selector to use for the portal which can be helpful in some cases, otherwise it creates a default using __ROOT_PORTAL__.
If it can't find the selector then it will create and attach a div.
NOTE: you could also statically add a div and specify a known id in pages/_document.tsx (or .jsx) if again using NextJS. Pass in that id and it will attempt to find and use it.
import { PropsWithChildren, useEffect, useState, useRef } from 'react';
import { createPortal } from 'react-dom';
export interface IPortal {
selector?: string;
}
const Portal = (props: PropsWithChildren<IPortal>) => {
props = {
selector: '__ROOT_PORTAL__',
...props
};
const { selector, children } = props;
const ref = useRef<Element>()
const [mounted, setMounted] = useState(false);
const selectorPrefixed = '#' + selector.replace(/^#/, '');
useEffect(() => {
ref.current = document.querySelector(selectorPrefixed);
if (!ref.current) {
const div = document.createElement('div');
div.setAttribute('id', selector);
document.body.appendChild(div);
ref.current = div;
}
setMounted(true);
}, [selector]);
return mounted ? createPortal(children, ref.current) : null;
};
export default Portal;
Usage
The below is a quickie example of using the portal. It does NOT take into account position etc. Just something simple to show you usage. Sky is limit from there :)
import React, { useState, CSSProperties } from 'react';
import Portal from './path/to/portal'; // Path to above
const modalStyle: CSSProperties = {
padding: '3rem',
backgroundColor: '#eee',
margin: '0 auto',
width: 400
};
const Home = () => {
const [visible, setVisible] = useState(false);
return (
<>
<p>Hello World <a href="#" onClick={() => setVisible(true)}>Show Modal</a></p>
<Portal>
{visible ? <div style={modalStyle}>Hello Modal! <a href="#" onClick={() => setVisible(false)}>Close</a></div> : null}
</Portal>
</>
);
};
export default Home;
const X = ({ children }) => ReactDOM.createPortal(children, 'dom-location')
Sharing my solution:
// PortalWrapperModal.js
import React, { useRef, useEffect } from 'react';
import ReactDOM from 'react-dom';
import $ from 'jquery';
const PortalWrapperModal = ({
children,
onHide,
backdrop = 'static',
focus = true,
keyboard = false,
}) => {
const portalRef = useRef(null);
const handleClose = (e) => {
if (e) e.preventDefault();
if (portalRef.current) $(portalRef.current).modal('hide');
};
useEffect(() => {
if (portalRef.current) {
$(portalRef.current).modal({ backdrop, focus, keyboard });
$(portalRef.current).modal('show');
$(portalRef.current).on('hidden.bs.modal', onHide);
}
}, [onHide, backdrop, focus, keyboard]);
return ReactDOM.createPortal(
<>{children(portalRef, handleClose)}</>,
document.getElementById('modal-root')
);
};
export { PortalWrapperModal };

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