React.useEffect stack execution prevents parent from setting defaults - reactjs

I have attached a simplified example that demonstrates my issue:
https://codesandbox.io/s/reactusehook-stack-issue-piq15
I have a parent component that receives a configuration, of which screen should be rendered. the rendered screen should have control over the parent appearance. In the example above I demonstrated it with colors. But the actual use case is flow screen that has next and back buttons which can be controlled by the child.
in the example I define common props for the screens:
type GenericScreenProps = {
setColor: (color: string) => void;
};
I create the first screen, that does not care about the color (parent should default)
const ScreenA = (props: GenericScreenProps) => {
return <div>screen A</div>;
};
I create a second screen that explicitly defines a color when mounted
const ScreenB = ({ setColor }: GenericScreenProps) => {
React.useEffect(() => {
console.log("child");
setColor("green");
}, [setColor]);
return <div>screen B</div>;
};
I create a map to be able to reference the components by an index
const map: Record<string, React.JSXElementConstructor<GenericScreenProps>> = {
0: ScreenA,
1: ScreenB
};
and finally I create the parent, that has a button that swaps the component and sets the default whenever the component changes
const App = () => {
const [screenId, setScreenId] = useState(0);
const ComponentToRender = map[screenId];
const [color, setColor] = useState("red");
React.useEffect(() => {
console.log("parent");
setColor("red"); // default when not set should be red
}, [screenId]);
const onButtonClick = () => setScreenId((screenId + 1) % Object.keys(map).length)
return (
<div>
<button style={{ color }} onClick={onButtonClick}>
Button
</button>
<ComponentToRender setColor={setColor} />
</div>
);
};
In this example, the default color should be red, for screen A. and green for the second screen.
However, the color stays red because useEffect is using a stack to execute the code. if you run the code you will see that once the button clicked there will be child followed by parent in log.
I have considered the following solution, but they are not ideal:
each child has to explicitly define the color, no way to enforce it without custom lint rules
convert the parent into a react class component, there has to be a hooks solution
This might be an anti-pattern where child component controls how its parent behave, by I could not identify a way of doing that without replicating the parent container for each screen. the reason I want to keep a single parent is to enable transition between the screens.

If I understood the problem correctly, there is no need to pass down setColor to the children. Making expressions more explicit might make a bit longer code, but I think it helps in readability. As what you shared is a simplified example, please let me know if it fits your real case:
const ScreenA = () => {
return <div>screen A</div>;
};
const ScreenB = () => {
return <div>screen B</div>;
};
const App = () => {
const [screen, setScreen] = useState<"a" | "b">("a");
const [color, setColor] = useState<"red" | "green">("red");
const onButtonClick = () => {
if (screen === "a") {
setScreen("b");
setColor("green");
} else {
setScreen("a");
setColor("red");
}
};
return (
<div>
<button style={{ color }} onClick={onButtonClick}>
Button
</button>
{screen === "a" ? <ScreenA /> : <ScreenB />}
</div>
);
};
render(<App />, document.getElementById("root"));

Related

React (+ Typescript) component not rerendering upon updating Context

I have a LaunchItem component which uses React.Context to get and set information to/from the local storage.
What I am trying to achieve is that, when the component updates the Context (and local storage), I want it to rerender with the new information, so that it then updates the state of a local button.
The problem is, although the Context seems to be updated as well as the contents of the local storage, the item is not rerendered. (when I refresh the page I can see the button has changed state, however, signifying that it is able to derive that information from the Context just fine.
I will now share some code and hopefully someone is able to understand what I might be missing, I thoroughly appreciate your help :)
Context provider setup
type FavoritesContextType = {
favorites: Favorites;
updateFavorites: (category: StorageCategory, item: string) => void;
};
export const FavoritesContext = createContext<FavoritesContextType>(
{} as FavoritesContextType
);
const FavoritesProvider: FC = ({ children }) => {
const [favorites, setFavorites] = useState<Favorites>(
getFromLocalStorage(SOME_CONSTANT)
);
const updateFavorites = (category: StorageCategory, item: string) => {
updateLocalStorage(category, item);
setFavorites(favorites);
};
return (
<FavoritesContext.Provider value={{ favorites, updateFavorites }}>
{children}
</FavoritesContext.Provider>
);
};
export const useFavoritesContext = () => useContext(FavoritesContext);
App.tsx
export const App = () => {
return (
<FavoritesProvider>
{/* Some routing wrapper and a few routes each rendering a component */}
<Route path="/launches" element={<Launches />} />
</FavoritesProvider>
)
Launches.tsx
export const LaunchItem = ({ launch }: LaunchItemProps) => {
const { favorites, updateFavorites } = useFavoritesContext();
const [isFavorite, setIsFavorite] = useState(false);
useEffect(() => {
if (favorites) {
setIsFavorite(
favorites.launches.includes(launch.flight_number.toString())
);
}
}, [favorites]);
return (
{/* The rest of the component, irrelevant */}
<FavoriteButton
isFavorite={isFavorite}
updateFavorites={() => {
updateFavorites(
StorageCategory.Launches,
launch.flight_number.toString()
);
}}
/>
)
FavoriteButton.tsx
export const FavoriteButton = ({
isFavorite,
updateFavorites,
}: FavoriteButtonProps) => {
const handleClick = (e: React.MouseEvent<HTMLAnchorElement, MouseEvent>) => {
e.preventDefault();
updateFavorites();
};
return (
// Using Link vs a Button to be able to preventDefault of parent Link
<Link
onClick={handleClick}
>
{/* The rest of the component, irrelevant */}
It seems as though in your updateFavorites function you're calling setFavorites and passing in the existing favorites value. Try instead writing your updateFavorites function as:
const updateFavorites = (category: StorageCategory, item: string) => {
updateLocalStorage(category, item);
setFavorites(getFromLocalStorage(SOME_CONSTANT));
};
There are other ways you could determine what value to pass to setFavorites but I reused your getFromLocalStorage function as I'm not sure how you're determining that state value.
By doing it this way you'll ensure that the value you're setting in setFavorites isn't the same as the existing favorites value and thus you'll trigger a re-render.

React ForwardRef: Property 'current' does not exist on type 'ForwardedRef<HTMLElement>'

I am trying to create a component that will track the vertical scroll. The catch is – the actual scroll container is not easily predictable (in this specific case it is neither window, document nor body – it is div#__next, due to CSS overflow rules).
I want to keep the component flexible and self-contained. So I've created a ref with DOM selector as an argument. I know it is far from idiomatic (to say the least), but it suprisingly seems to be working:
// Parent component
import { useRef } from "react"
const Article = (props) => {
const scrollContainerRef = useRef<HTMLElement | null>(
document.querySelector("#__next") // <-- the scroll container reference
)
return (
<SomeContent>
<ScrollToTop treshold={640} ref={scrollContainerRef} />
</SomeContent>
)
// ScrollToTop
const ScrollToTop = forwardRef(
({ treshold }, ref) => {
const [visible, setVisible] = useState(false)
useEffect(() => {
if (ref?.current) {
ref.current.addEventListener("scroll", throttle(toggleVisible, 300))
return () => {
ref.current.removeEventListener("scroll", throttle(toggleVisible, 300))
}
}
}, [])
// …
So what's the problem? the current one is Typescript. I've spent hours trying to get the types right, but to no avail. The parent component is red squigly lines free (unless I pass globalThis, which seems to work at least in CodeSandbox), but the ScrollToTop is compaining whenever I am accessing current property:
Property 'current' does not exist on type 'ForwardedRef<HTMLElement>'.
I've tried to use React.MutableRefObject<HTMLElement | null /* or other T's */>, both in parent and in child, but it didn't help.
Any ideas how to get the types to match? Or is this a silly idea from the beginning?
CodeSandbox demo
Refs might be objects with a .current property, but they might also be functions. So you can't assume that a forwarded ref has a .current property.
I think it's a mistake to use forwardRef at all here. The purpose of forwardRef is to allow a parent component to get access to an element in a child component. But instead, the parent is the one finding the element, and then you're passing it to the child for it to use. I would use a regular state and prop for that:
const Article = (props) => {
const [scrollContainer, setScrollContainer] = useState<HTMLElement | null>(() => {
return document.querySelector("#__next");
});
return (
<SomeContent>
<ScrollToTop treshold={640} scrollContainer={scrollContainer} />
</SomeContent>
)
interface ScrollToTopProps {
treshold: number;
scrollContainer: HTMLElement | null;
}
const ScrollToTop = ({ treshold, scrollContainer }: ScrollToTopProps) => {
const [visible, setVisible] = useState(false);
useEffect(() => {
if (scrollContainer) {
const toggle = throttle(toggleVisible, 300);
scrollContainer.addEventListener("scroll", toggle);
return () => {
scrollContainer.removeEventListener("scroll", toggle);
}
}
}, [scrollContainer]);
// ...
}

Tooltip delay on hover with RXJS

I'm trying to add tooltip delay (300msemphasized text) using rxjs (without setTimeout()). My goal is to have this logic inside of TooltipPopover component which will be later be reused and delay will be passed (if needed) as a prop.
I'm not sure how can I add "delay" logic inside of TooltipPopover component using rxjs?
Portal.js
const Portal = ({ children }) => {
const mount = document.getElementById("portal-root");
const el = document.createElement("div");
useEffect(() => {
mount.appendChild(el);
return () => mount.removeChild(el);
}, [el, mount]);
return createPortal(children, el);
};
export default Portal;
TooltipPopover.js
import React from "react";
const TooltipPopover = ({ delay??? }) => {
return (
<div className="ant-popover-title">Title</div>
<div className="ant-popover-inner-content">{children}</div>
);
};
App.js
const App = () => {
return (
<Portal>
<TooltipPopover>
<div>
Content...
</div>
</TooltipPopover>
</Portal>
);
};
Then, I'm rendering TooltipPopover in different places:
ReactDOM.render(<TooltipPopover delay={1000}>
<SomeChildComponent/>
</TooltipPopover>, rootEl)
Here would be my approach:
mouseenter$.pipe(
// by default, the tooltip is not shown
startWith(CLOSE_TOOLTIP),
switchMap(
() => concat(timer(300), NEVER).pipe(
mapTo(SHOW_TOOLTIP),
takeUntil(mouseleave$),
endWith(CLOSE_TOOLTIP),
),
),
distinctUntilChanged(),
)
I'm not very familiar with best practices in React with RxJS, but this would be my reasoning. So, the flow would be this:
on mouseenter$, start the timer. concat(timer(300), NEVER) is used because although after 300ms the tooltip should be shown, we only want to hide it when mouseleave$ emits.
after 300ms, the tooltip is shown and will be closed mouseleave$
if mouseleave$ emits before 300ms pass, the CLOSE_TOOLTIP will emit, but you could avoid(I think) unnecessary re-renders with the help of distinctUntilChanged

React hooks. Update component passed as param via onClick after one of it's prop was changed

Hi guys) I have a strange question may be, but I'm at a dead end.
I have my own custom hook.
const useModal = (Content?: ReactNode, options?: ModalOptions) => {
const { isOpen, close: contextClose, open: contextOpen, setContent } = useContext(
ModalContext,
)
const [customOpenContent, setCustomOpenContent] = useState<ReactNode>()
const showModal = useCallback(
(customContent?: ReactNode) => {
if (!isNil(customContent)) {
setCustomOpenContent(customContent)
contextOpen(customContent, options)
} else contextOpen(Content, options)
},
[contextOpen, Content, options],
)
const hideModal = useCallback(() => {
contextClose()
}, [contextClose])
return { isOpen, close: hideModal, open: showModal, setContent }
}
It is quite simple.
Also i have component which uses this hook
const App: React.FC = () => {
const [loading, setLoading] = useState(false)
const { open } = useModal(null, { deps: [loading] })
useEffect(() => {
setTimeout(() => {
setLoading(true)
}, 10000)
})
const buttonCallback = useCallback(() => {
open(<Button disabled={!loading}>Loading: {loading.toString()}</Button>)
}, [loading, open])
return (
<Page title="App">
<Button onClick={buttonCallback}>Open Modal</Button>
</Page>
)
}
Main problem is - Button didn't became enabled because useModal hook doesn't know anything about changes.
May be you have an idea how to update this component while it's props are updated? And how to do it handsomely ))
Context isn't the best solution to this problem. What you want is a Portal instead. Portals are React's solution to rendering outside of the current React component hierarchy. How to use React Portal? is a basic example, but as you can see, just going with the base React.Portal just gives you the location to render.
Here's a library that does a lot of the heavy lifting for you: https://github.com/wellyshen/react-cool-portal. It has typescript definitions and provides an easy API to work with.
Here's your example using react-cool-portal.
import usePortal from "react-cool-portal";
const App = () => {
const [loading, setLoading] = useState(false);
const { Portal, isShow, toggle } = usePortal({ defaultShow: false });
useEffect(() => {
setTimeout(() => {
setLoading(true);
}, 10000);
});
const buttonCallback = useCallback(() => {
toggle();
}, [toggle]);
return (
<div title="App" style={{ backgroundColor: "hotpink" }}>
<button onClick={buttonCallback}>
{isShow ? "Close" : "Open"} Modal
</button>
<Portal>
<button disabled={!loading}>Loading: {loading.toString()}</button>
</Portal>
<div>{loading.toString()}</div>
</div>
);
};
Basic CodeSandbox Example
There are more detailed ones within the react-cool-portal documentation.
For more detail of the issues with the Context solution you were trying, is that React Elements are just a javascript object. React then uses the object, it's location in the tree, and it's key to determine if they are the same element. React doesn't actually care or notice where you create the object, only it's location in the tree when it is rendered.
The disconnect in your solution is that when you pass the element to the open function in buttonCallback, the element is created at that point. It's a javascript object that then is set as the content in your context. At that point, the object is set and won't change until you called open again. If you set up your component to call open every time the relevant state changes, you could get it working that way. But as I mentioned earlier, context wasn't built for rendering components outside of the current component; hence why some really weird workarounds would be required to get it working.

How to target a specific item to toggleClick on using React Hooks?

I have a navbar component with that actual info being pulled in from a CMS. Some of the nav links have a dropdown component onclick, while others do not. I'm having a hard time figuring out how to target a specific menus index with React Hooks - currently onClick, it opens ALL the dropdown menus at once instead of the specific one I clicked on.
The prop toggleOpen is being passed down to a styled component based on the handleDropDownClick event handler.
Heres my component.
const NavBar = props => {
const [links, setLinks] = useState(null);
const [notFound, setNotFound] = useState(false);
const [isOpen, setIsOpen] = useState(false);
const fetchLinks = () => {
if (props.prismicCtx) {
// We are using the function to get a document by its uid
const data = props.prismicCtx.api.query([
Prismic.Predicates.at('document.tags', [`${config.source}`]),
Prismic.Predicates.at('document.type', 'navbar'),
]);
data.then(res => {
const navlinks = res.results[0].data.nav;
setLinks(navlinks);
});
}
return null;
};
const checkForLinks = () => {
if (props.prismicCtx) {
fetchLinks(props);
} else {
setNotFound(true);
}
};
useEffect(() => {
checkForLinks();
});
const handleDropdownClick = e => {
e.preventDefault();
setIsOpen(!isOpen);
};
if (links) {
const linkname = links.map(item => {
// Check to see if NavItem contains Dropdown Children
return item.items.length > 1 ? (
<Fragment>
<StyledNavBar.NavLink onClick={handleDropdownClick} href={item.primary.link.url}>
{item.primary.label[0].text}
</StyledNavBar.NavLink>
<Dropdown toggleOpen={isOpen}>
{item.items.map(subitem => {
return (
<StyledNavBar.NavLink href={subitem.sub_nav_link.url}>
<span>{subitem.sub_nav_link_label[0].text}</span>
</StyledNavBar.NavLink>
);
})}
</Dropdown>
</Fragment>
) : (
<StyledNavBar.NavLink href={item.primary.link.url}>
{item.primary.label[0].text}
</StyledNavBar.NavLink>
);
});
// Render
return (
<StyledNavBar>
<StyledNavBar.NavContainer wide>
<StyledNavBar.NavWrapper row center>
<Logo />
{linkname}
</StyledNavBar.NavWrapper>
</StyledNavBar.NavContainer>
</StyledNavBar>
);
}
if (notFound) {
return <NotFound />;
}
return <h2>Loading Nav</h2>;
};
export default NavBar;
Your problem is that your state only handles a boolean (is open or not), but you actually need multiple booleans (one "is open or not" for each menu item). You could try something like this:
const [isOpen, setIsOpen] = useState({});
const handleDropdownClick = e => {
e.preventDefault();
const currentID = e.currentTarget.id;
const newIsOpenState = isOpen[id] = !isOpen[id];
setIsOpen(newIsOpenState);
};
And finally in your HTML:
const linkname = links.map((item, index) => {
// Check to see if NavItem contains Dropdown Children
return item.items.length > 1 ? (
<Fragment>
<StyledNavBar.NavLink id={index} onClick={handleDropdownClick} href={item.primary.link.url}>
{item.primary.label[0].text}
</StyledNavBar.NavLink>
<Dropdown toggleOpen={isOpen[index]}>
// ... rest of your component
Note the new index variable in the .map function, which is used to identify which menu item you are clicking.
UPDATE:
One point that I was missing was the initialization, as mention in the other answer by #MattYao. Inside your load data, do this:
data.then(res => {
const navlinks = res.results[0].data.nav;
setLinks(navlinks);
setIsOpen(navlinks.map((link, index) => {index: false}));
});
Not related to your question, but you may want to consider skipping effects and including a key to your .map
I can see the first two useState hooks are working as expected. The problem is your 3rd useState() hook.
The issue is pretty obvious that you are referring the same state variable isOpen by a list of elements so they all have the same state. To fix the problems, I suggest the following way:
Instead of having one value of isOpen, you will need to initialise the state with an array or Map so you can refer each individual one:
const initialOpenState = [] // or using ES6 Map - new Map([]);
In your fetchLink function callback, initialise your isOpen state array values to be false. So you can put it here:
data.then(res => {
const navlinks = res.results[0].data.nav;
setLinks(navlinks);
// init your isOpen state here
navlinks.forEach(link => isOpen.push({ linkId: link.id, value: false })) //I suppose you can get an id or similar identifers
});
In your handleClick function, you have to target the link object and set it to true, instead of setting everything to true. You might need to use .find() to locate the link you are clicking:
handleClick = e => {
const currentOpenState = state;
const clickedLink = e.target.value // use your own identifier
currentOpenState[clickedLink].value = !currentOpenState[clickedLink].value;
setIsOpen(currentOpenState);
}
Update your component so the correct isOpen state is used:
<Dropdown toggleOpen={isOpen[item].value}> // replace this value
{item.items.map(subitem => {
return (
<StyledNavBar.NavLink href={subitem.sub_nav_link.url}>
<span>{subitem.sub_nav_link_label[0].text}</span>
</StyledNavBar.NavLink>
);
})}
</Dropdown>
The above code may not work for you if you just copy & paste. But it should give you an idea how things should work together.

Resources