I'm using this lib to create a modal
I have 3 components: Table, Modal and List
Table has Modal (a custom React Modal), and the body of Modal will be List.
Now the problem is, List has some functions which change the states of Table, so when I do something that can make Table's state change, Table and Modal will be re-rendered when Modal is re-rendered, it re-creates a new List which leads to lost all stuffs I'm doing with List.
Here is a simple version of my app. link
Now I don't want List to be re-created each time Modal is re-rendered. Is there any way to archive that? (I don't want to create a modal myself or use global state management in this case)
import { useEffect, useMemo, useState } from "react";
import ReactModal from "react-modal";
ReactModal.setAppElement("#root");
const List = ({ onClick }) => {
useEffect(() => {
console.log("List is mounted");
}, []);
return <button onClick={onClick}>Click me!</button>;
};
const Modal = ({ state, body, isOpen }) => {
useEffect(() => {
console.log("Modal is re-rendered");
});
return (
<div
id="react modal wrapper"
style={{
display: `${isOpen ? "block" : "none"}`
}}
>
<ReactModal isOpen={isOpen}>
<div>
state is {state}
<br />
{body}
</div>
</ReactModal>
</div>
);
};
const Table = ({ state, onClick, isOpen }) => {
useEffect(() => {
console.log("Table is re-rendered");
});
const memorizedList = useMemo(() => <List onClick={onClick} />, []);
return (
<div>
state: {state}
<Modal state={state} body={memorizedList} isOpen={isOpen} />
</div>
);
};
const App = () => {
const [state, setState] = useState(1);
const onClick = () => setState((v) => v + 1);
return (
<div>
<button onClick={onClick}>Change state</button>
<Table state={state} onClick={onClick} isOpen={state % 2 === 0} />
</div>
);
};
export default App;
Related
i have a modal component in my react app and i need to close it on click outside
import React from "react";
import ReactDOM from "react-dom";
import style from "./Modal.module.scss";
const Modal = ({ isShowing, hide, childrenContent, childrenHeader }) =>
isShowing
? ReactDOM.createPortal(
<React.Fragment>
<div className={style.modalOverlay} />
<div
className={style.modalWrapper}
aria-modal
aria-hidden
tabIndex={-1}
role="dialog"
>
<div className={style.modal}>
<div className={style.modalHeader}>
{childrenHeader}
<button
type="button"
className={style.modalCloseButton}
data-dismiss="modal"
aria-label="Close"
onClick={hide}
>
<span aria-hidden="true">×</span>
</button>
</div>
{childrenContent}
</div>
</div>
</React.Fragment>,
document.body
)
: null;
export default Modal;
i was try to use this solution but it's not work in my code, how can i fix it?
Just a tip, when looking at the html you can use the native <dialog> tag, this is the semantically correct way to display a dialog type pop-up box, which yours looks to be.
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog
Dialog has a showModal() method, and a .close() method. This would be a better way of displaying a pop-up type dialog, than using <div> tags. It also allows you to use the native HTML5 methods, rather than trying to provide a work around using React.
I would reccomend this method over trying to look for work arounds
const Modal = ({ children, showModal, toggleModal }) => {
const wrapperRef = React.useRef(null);
const closeModal = React.useCallback(
({ target }) => {
if (
wrapperRef &&
wrapperRef.current &&
!wrapperRef.current.contains(target)
) {
toggleModal();
}
},
[toggleModal]
);
React.useEffect(() => {
document.addEventListener("click", closeModal, { capture: true });
return () => {
document.removeEventListener("click", closeModal, { capture: true });
};
}, [closeModal]);
return showModal
? ReactDOM.createPortal(
<>
<div ref={wrapperRef} className="modal">
{children}
</div>
</>,
document.body
)
: null;
};
Modal.propTypes = {
children: PropTypes.node.isRequired,
showModal: PropTypes.bool.isRequired,
toggleModal: PropTypes.func.isRequired
};
export default Modal;
in your parent component :
const Parent = () => {
const [showModal, setModalState] = React.useState(false);
const toggleModal = React.useCallback(() => {
setModalState((prevState) => !prevState);
}, []);
return (
<div>
<Modal showModal={showModal} toggleModal={toggleModal}>
<h1>Hello!</h1>
... some other childrens
<button
onClick={toggleModal}
>
Close
</button>
</Modal>
</div>
);
};
I need to toggle multiple blocks with true/false in react state, but true and false works for all blocks at the same time.
import { useState } from "react";
...
const [toggleThisElement, setToggleThisElement] = useState(false);
...
{
data.map((d, id) => {
return (
<div className="single-history" key={id}>
<div className="h-head">
click this div for toggle h-info block
</div>
<div className="h-info">toggling block</div>
</div>
)
})
}
Currently, all your toggle items share the same state. To avoid that create a separate component for toggling logic called ToggleItem as below.
import { useState } from "react";
const ToggleItem = ({ discription, id }) => {
const [toggleThisElement, setToggleThisElement] = useState(false);
return (
<div className="single-history" key={id}>
<button
className="h-head"
onClick={() => setToggleThisElement((prev) => !prev)}
>
click this btn for toggle h-info block {id}
</button>
{toggleThisElement && <div className="h-info">{discription}</div>}
</div>
);
};
export default function App() {
const data = ["first", "second", "third"];
return (
<>
{data.map((d, id) => {
return <ToggleItem id={id} discription={d} />;
})}
</>
);
}
Let's say that we have a React app with two pages A and B using a shared menu component Menu.
Our app renders either page A or page B, like the example below:
const Menu = (props) => {
React.useEffect(()=>{
console.log("The menu remounted");
}, []);
return (
<div id="menu" className="has-scrollbar">
<button onClick={() => props.onClick('a')}>A</button>
<button onClick={() => props.onClick('b')}>B</button>
</div>
);
}
const PageA = (props) => {
const .. = useSomeHooksUsedByPageA();
return (
<div>
<Menu {...somePropsFromPageA} />
<div>Content of page A</div>
</div>
);
}
const PageB = (props) => (
const .. = useSomeHooksUsedByPageB();
<div>
<Menu {...somePropsFromPageB} />
<div>Content of page B</div>
</div>
);
const App = () => {
const [pageKey, setPageKey] = React.useState("a");
switch (pageKey)
{
case "a":
return <PageA key="1" onClick={setPageKey} />;
case "b":
return <PageB key="1" onClick={setPageKey} />;
}
return "true"
}
Now, every time we switch pages (from A to B, or B to A), the menu is remounted and a message is printed to the console.
Using this component hierarchy where the menu receives props from the page, is there any way to tell React not to remount the menu when we switch pages?
(A typical use-case could be that the menu has a scroll, and we want to keep the scroll position when navigating different pages.)
Help is greatly appreciated!
One potential solution for this problem is to move <Menu/> into the <App/> component, and render each page after the menu.
This provides a couple of benefits:
The Menu won't be re-rendered whenever the page changes.
The onClick function does not need to be passed through props on each page just to provide it to the <Menu/> component nested within.
const Menu = (props) => {
React.useEffect(() => {
console.log("The menu remounted");
}, []);
return (
<div id="menu" className="has-scrollbar">
<button onClick={() => props.onClick("a")}>A</button>
<button onClick={() => props.onClick("b")}>B</button>
</div>
);
};
const PageA = () => (
<div>
<div>Content of page A</div>
</div>
);
const PageB = () => (
<div>
<div>Content of page B</div>
</div>
);
const App = () => {
const [pageKey, setPageKey] = React.useState("a");
let page;
switch (pageKey) {
case "b":
page = <PageB key="2" />;
break;
default:
page = <PageA key="3" />;
break;
}
return (
<>
<Menu onClick={setPageKey} />
{page}
</>
);
};
ReactDOM.render(<App />, document.querySelector("#app"))
Edit
Further to #glingt's comment regarding the hierarchy and how this needs to function, Context might be a good candidate for the use case. If pages need to update the <Menu/> component's props, then using context to manage state between the menu and pages might be a better solution in terms of architecture. Instead of rendering many <Menu/> components inside of each child, only one <Menu/> can be rendered higher up in the tree. This results in the component mounting once rather than many times with each child. Effectively, context manages the state of the menu, and provides methods to update state to any children under the provider. In this case, both child pages and the menu can update and respond to state updates.
import "./styles.css";
import React, { useContext, useMemo, useState } from "react";
// Create an instance of context so we are able to update the menu from lower in the tree
const menuContext = React.createContext({});
// Add state to the context provider. Wrap props earlier in the tree with this component.
const MenuContext = ({ children }) => {
const [pageKey, setPageKey] = useState("a");
const value = useMemo(() => ({ pageKey, setPageKey }), [pageKey]);
return <menuContext.Provider value={value}>{children}</menuContext.Provider>;
};
// The menu component which will:
// 1. Update the menuContext when the user selects a new pageKey
// 2. Respond to updates made to the pageKey by other components (in this case pages)
const Menu = () => {
const { pageKey, setPageKey } = useContext(menuContext);
React.useEffect(() => {
console.log("The menu remounted");
}, []);
return (
<div id="menu" className="has-scrollbar">
<button
onClick={() => setPageKey("a")}
style={{ color: pageKey === "a" ? "blue" : "red" }}
>
A
</button>
<button
onClick={() => setPageKey("b")}
style={{ color: pageKey === "b" ? "blue" : "red" }}
>
B
</button>
</div>
);
};
// In each page, we are able to update a value that is consumed by the menu using setPageKey
const PageA = () => {
const { setPageKey } = useContext(menuContext);
return (
<div>
<div>Content of page A</div>
<button onClick={() => setPageKey("b")}>Go to page B</button>
</div>
);
};
const PageB = () => {
const { setPageKey } = useContext(menuContext);
return (
<div>
<div>Content of page B</div>
<button onClick={() => setPageKey("a")}>Go to page A</button>
</div>
);
};
const PageComponent = () => {
const { pageKey } = useContext(menuContext);
switch (pageKey) {
case "b":
return <PageB key="2" />;
default:
return <PageA key="1" />;
}
};
const App = () => (
<MenuContext>
<Menu />
<PageComponent />
</MenuContext>
);
ReactDOM.render(<App />, document.querySelector("#app"))
I have 2 components. In the parent component I have this:
const Demo = () => {
const [state, setState] = useState(true);
const onChange = useCallback(
(value: string) => {
console.log(value);
},
[],
);
return (
<div className="a">
<button onClick={() => setState(!state)}>sds</button>
<div className="123">
<Bar searchHandler={onChangeSearchHandler} />
</div>
</div>
);
};
In the Bar component I have this:
const Bar = ({ searchHandler }) => {
console.log('bar');
return (
<div>
<input type="text" onChange={(value) => searchHandler(value.target.value)} />
</div>
);
};
Wrapping onChange with useCallback I expect to cache the function and when I click on <button onClick={() => setState(false)}>sds</button> I don't want to render Bar component, but it is triggered. Why Bar component is triggered and how to prevent this with useCallback?
This has nothing to do with the onChange function you're wrapping with useCallback. Bar gets re-rendered because you're changing the state through setState in its parent component. When you change the state in a component all its child components get re-rendered.
You can verify it yourself by trying this:
const Demo = () => {
const [state, setState] = useState(true);
return (
<div className="a">
<button onClick={() => setState(!state)}>sds</button>
<div className="123">
<Bar />
</div>
</div>
);
};
const Bar = ({ searchHandler }) => {
console.log('bar');
return (
<div></div>
);
};
You'll see that the Bar gets re-rerender anyway.
If you want to skip re-rerendring any of the child components, you should memoize them using React.memo when applicable.
Also, you should familiarize yourself with how state in react works and how does it affect the nested components as this is a main concept.
The issue is that you haven't used React.memo on Bar component. The function useCallback works only if you use HOC from memo.
try this, in Bar component create this wrapped component:
const WrappedBar = React.memo(Bar);
and in parent component use this wrapped bar:
const Demo = () => {
const [state, setState] = useState(true);
const onChange = useCallback(
(value: string) => {
console.log(value);
},
[],
);
return (
<div className="a">
<button onClick={() => setState(!state)}>sds</button>
<div className="123">
<WrappedBar searchHandler={onChangeSearchHandler} />
</div>
</div>
);
};
I'm looking for the easiest solution to pass data from a child component to his parent.
I've heard about using Context, pass trough properties or update props, but I don't know which one is the best solution.
I'm building an admin interface, with a PageComponent that contains a ChildComponent with a table where I can select multiple line. I want to send to my parent PageComponent the number of line I've selected in my ChildComponent.
Something like that :
PageComponent :
<div className="App">
<EnhancedTable />
<h2>count 0</h2>
(count should be updated from child)
</div>
ChildComponent :
const EnhancedTable = () => {
const [count, setCount] = useState(0);
return (
<button onClick={() => setCount(count + 1)}>
Click me {count}
</button>
)
};
I'm sure it's a pretty simple thing to do, I don't want to use redux for that.
A common technique for these situations is to lift the state up to the first common ancestor of all the components that needs to use the state (i.e. the PageComponent in this case) and pass down the state and state-altering functions to the child components as props.
Example
const { useState } = React;
function PageComponent() {
const [count, setCount] = useState(0);
const increment = () => {
setCount(count + 1)
}
return (
<div className="App">
<ChildComponent onClick={increment} count={count} />
<h2>count {count}</h2>
(count should be updated from child)
</div>
);
}
const ChildComponent = ({ onClick, count }) => {
return (
<button onClick={onClick}>
Click me {count}
</button>
)
};
ReactDOM.render(<PageComponent />, document.getElementById("root"));
<script src="https://unpkg.com/react#16/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom#16/umd/react-dom.development.js"></script>
<div id="root"></div>
You can create a method in your parent component, pass it to child component and call it from props every time child's state changes, keeping the state in child component.
const EnhancedTable = ({ parentCallback }) => {
const [count, setCount] = useState(0);
return (
<button onClick={() => {
const newValue = count + 1;
setCount(newValue);
parentCallback(newValue);
}}>
Click me {count}
</button>
)
};
class PageComponent extends React.Component {
callback = (count) => {
// do something with value in parent component, like save to state
}
render() {
return (
<div className="App">
<EnhancedTable parentCallback={this.callback} />
<h2>count 0</h2>
(count should be updated from child)
</div>
)
}
}
To make things super simple you can actually share state setters to children and now they have the access to set the state of its parent.
example:
Assume there are 4 components as below,
function App() {
return (
<div className="App">
<GrandParent />
</div>
);
}
const GrandParent = () => {
const [name, setName] = useState("i'm Grand Parent");
return (
<>
<div>{name}</div>
<Parent setName={setName} />
</>
);
};
const Parent = params => {
return (
<>
<button onClick={() => params.setName("i'm from Parent")}>
from Parent
</button>
<Child setName={params.setName} />
</>
);
};
const Child = params => {
return (
<>
<button onClick={() => params.setName("i'm from Child")}>
from Child
</button>
</>
);
};
so grandparent component has the actual state and by sharing the setter method (setName) to parent and child, they get the access to change the state of the grandparent.
you can find the working code in below sandbox,
https://codesandbox.io/embed/async-fire-kl197
IF we Have Parent Class Component and Child function component this is how we going to access child component useStates hooks value :--
class parent extends Component() {
constructor(props){
super(props)
this.ChildComponentRef = React.createRef()
}
render(){
console.log(' check child stateValue: ',
this.ChildComponentRef.current.info);
return (<> <ChildComponent ref={this.ChildComponentRef} /> </>)
}
}
Child Component we would create using
React.forwardRef((props, ref) => (<></>))
. and
useImperativeHandle(ref, createHandle, [deps])
to customizes the instance value that is exposed to parent components
const childComponent = React.forwardRef((props, ref) => {
const [info, setInfo] = useState("")
useEffect(() => {
axios.get("someUrl").then((data)=>setInfo(data))
})
useImperativeHandle(ref, () => {
return {
info: info
}
})
return (<> <h2> Child Component <h2> </>)
})
I had to do this in type script. The object-oriented aspect would need the dev to add this callback method as a field in the interface after inheriting from parent and the type of this prop would be Function. I found this cool!
Here's an another example of how we can pass state directly to the parent.
I modified a component example from react-select library which is a CreatableSelect component. The component was originally developed as class based component, I turned it into a functional component and changed state manipulation algorithm.
import React, {KeyboardEventHandler} from 'react';
import CreatableSelect from 'react-select/creatable';
import { ActionMeta, OnChangeValue } from 'react-select';
const MultiSelectTextInput = (props) => {
const components = {
DropdownIndicator: null,
};
interface Option {
readonly label: string;
readonly value: string;
}
const createOption = (label: string) => ({
label,
value: label,
});
const handleChange = (value: OnChangeValue<Option, true>, actionMeta: ActionMeta<Option>) => {
console.group('Value Changed');
console.log(value);
console.log(`action: ${actionMeta.action}`);
console.groupEnd();
props.setValue(value);
};
const handleInputChange = (inputValue: string) => {
props.setInputValue(inputValue);
};
const handleKeyDown: KeyboardEventHandler<HTMLDivElement> = (event) => {
if (!props.inputValue) return;
switch (event.key) {
case 'Enter':
case 'Tab':
console.group('Value Added');
console.log(props.value);
console.groupEnd();
props.setInputValue('');
props.setValue([...props.value, createOption(props.inputValue)])
event.preventDefault();
}
};
return (
<CreatableSelect
id={props.id}
instanceId={props.id}
className="w-100"
components={components}
inputValue={props.inputValue}
isClearable
isMulti
menuIsOpen={false}
onChange={handleChange}
onInputChange={handleInputChange}
onKeyDown={handleKeyDown}
placeholder="Type something and press enter..."
value={props.value}
/>
);
};
export default MultiSelectTextInput;
I call it from the pages of my next js project like this
import MultiSelectTextInput from "../components/Form/MultiSelect/MultiSelectTextInput";
const NcciLite = () => {
const [value, setValue] = useState<any>([]);
const [inputValue, setInputValue] = useState<any>('');
return (
<React.Fragment>
....
<div className="d-inline-flex col-md-9">
<MultiSelectTextInput
id="codes"
value={value}
setValue={setValue}
inputValue={inputValue}
setInputValue={setInputValue}
/>
</div>
...
</React.Fragment>
);
};
As seen, the component modifies the page's (parent page's) state in which it is called.
I've had to deal with a similar issue, and found another approach, using an object to reference the states between different functions, and in the same file.
import React, { useState } from "react";
let myState = {};
const GrandParent = () => {
const [name, setName] = useState("i'm Grand Parent");
myState.name=name;
myState.setName=setName;
return (
<>
<div>{name}</div>
<Parent />
</>
);
};
export default GrandParent;
const Parent = () => {
return (
<>
<button onClick={() => myState.setName("i'm from Parent")}>
from Parent
</button>
<Child />
</>
);
};
const Child = () => {
return (
<>
<button onClick={() => myState.setName("i'm from Child")}>
from Child
</button>
</>
);
};