hi is it safe to call function props inside setState function param?
(if onToggle is used by the parent for setting another state), how it's affect the lifecycle / event persist?
example:
const myComponent = ({onToggle}) => {
const [active, setActive] = useState(false);
//use this
const handleChange = (e) => {
setActive(prev => {
onToggle(e, !prev);
return !prev;
});
}
//instead of this
const handleChange = (e) => {
setActive(prev => !prev);
onToggle(e. !active);
}
return (
<>
<button type="button" onChange={handleChange} />
{active && <div>ACTIVE</div>}
</>
)
}
because react says that update state may asynchronous:
https://reactjs.org/docs/state-and-lifecycle.html#state-updates-may-be-asynchronous
Related
I have a React HOC that hides a flyover/popup/dropdown, whenever I click outside the referenced component. It works perfectly fine when using local state. My HOC looks like this:
export default function withClickOutside(WrappedComponent) {
const Component = props => {
const [open, setOpen] = useState(false);
const ref = useRef();
useEffect(() => {
const handleClickOutside = event => {
if (ref?.current && !ref.current.contains(event.target)) {
setOpen(false);
}
};
document.addEventListener('mousedown', handleClickOutside);
return () => setOpen(false);
}, [ref]);
return <WrappedComponent open={open} setOpen={setOpen} ref={ref} {...props} />;
};
return Component;
}
When in use I just wrap up the required component with the HOC function
const TestComponent = () => {
const ref = useRef();
return <Wrapper ref={ref} />;
}
export default withClickOutside(TestComponent);
But I have some flyover containers that are managed from Redux when they are shown, or when they are hidden. When the flyover is shown, I want to have the same behavior, by clicking outside the referenced component to hide it right away. Here's a example of a flyover:
const { leftFlyoverOpen } = useSelector(({ toggles }) => toggles);
return (
<div>
<Wrapper>
<LeftFlyoverToggle
onClick={() => dispatch({ type: 'LEFT_FLYOVER_OPEN' })}
>
...
</Wrapper>
{leftFlyoverOpen && <LeftFlyover />}
{rightFlyoverOpen && <RightFlyover />}
</div>
);
Flyover component looks pretty straightforward:
const LefFlyover = () => {
return <div>...</div>;
};
export default LefFlyover;
Question: How can I modify the above HOC to handle Redux based flyovers/popup/dropdown?
Ideally I would like to handle both ways in one HOC, but it's fine if the examples will be only for Redux solution
You have a few options here. Personally, I don't like to use HOC's anymore. Especially in combination with functional components.
One possible solution would be to create a generic useOnClickOutside hook which accepts a callback. This enables you to dispatch an action by using the useDispatch hook inside the component.
export default function useOnClickOutside(callback) {
const [element, setElement] = useState(null);
useEffect(() => {
const handleClickOutside = event => {
if (element && !element.contains(event.target)) {
callback();
}
};
if (element) {
document.addEventListener('mousedown', handleClickOutside);
}
return () => document.removeEventListener('mousedown', handleClickOutside);
}, [element, callback]);
return setElement;
}
function LeftFlyOver() {
const { leftFlyoverOpen } = useSelector(({ toggles }) => toggles);
const dispatch = useDispatch();
const setElement = useOnClickOutside(() => {
dispatch({ type: 'LEFT_FLYOVER_CLOSE' });
});
return (
<Dialog open={leftFlyoverOpen} ref={ref => setElement(ref)}>
...
</Dialog>
)
}
Child component
export const FlightRange = (props) => {
const [value, setValue] = useState(props.value);
return (
<>
<input
type='range'
min={1000}
max={50000}
step="500"
value={value}
onChange={(e) => {
setValue(e.target.value);
props.handleSliderChange(value);
}}
/>
<span>{value}</span>
</>
);
};
parent component
useEffect(() => {
const result = axios.get('http://localhost:8000/')
.then((res) => res.json())
.then((data) => {
const flightData = data.filter((value) => {
return (
valuesplit(' ')[1] < priceSlider
);
});
})
}, [priceSlider]);
return(
<Child value={priceSlider} handleSliderChange={(value)=> setPriceSlider(value)} />
)
useEffect does not get called when the slider is changed the first time. It gets called a second time with the stale (previous value) value.
What am I missing?
in onChange you need to call like this
onChange={(e) => {
setValue(e.target.value);
props.handleSliderChange(e.target.value);
}}
since value is not updated instantly when you call setValue(e.target.value); , value will have previous value that you are passing in props.handleSliderChang(value)
to know how setState works see this answer
The issue is on the onClick callback of FlightRange input, see comments on code below
onChange = {(e) => {
setValue(e.target.value); // this is async
// therefore, the value you are passing here is not the same as e.target.value but simply the value before setting the state
props.handleSliderChange(value);
}}
So to fix this just refactor props.handleSliderChange argument to e.target.value
onChange = {(e) => {
setValue(e.target.value);
props.handleSliderChange(e.target.value);
}}
It because the child is having it's own life cycle since you are using useState in child. so whatever props you pass to your child, the child's state won't affected.
plus you are passing incorrect value in onChange
Solution: just use the props value directly on child (do not store in state):
export const FlightRange = (props) => {
const { value, handleSliderChange } = props;
return (
<>
<input
type='range'
min={1000}
max={50000}
step="500"
value={value}
onChange={(e) => {
handleSliderChange(e.target.value);
}}
/>
<span>{value}</span>
</>
);
};
This is a follow-up to Refactoring class component to functional component with hooks, getting Uncaught TypeError: func.apply is not a function
I've declared a functional component Parameter that pulls in values from actions/reducers using the useSelector hook:
const Parameter = () => {
let viz = useSelector(state => state.fetchDashboard);
const parameterSelect = useSelector(state => state.fetchParameter)
const parameterCurrent = useSelector(state => state.currentParameter)
const dispatch = useDispatch();
const drawerOpen = useSelector(state => state.filterIconClick);
const handleParameterChange = (event, valKey, index, key) => {
parameterCurrent[key] = event.target.value;
return (
prevState => ({
...prevState,
parameterCurrent: parameterCurrent
}),
() => {
viz
.getWorkbook()
.changeParameterValueAsync(key, valKey)
.then(function () {
//some code describing an alert
});
})
.otherwise(function (err) {
alert(
//some code describing a different alert
);
});
}
);
};
const classes = useStyles();
return (
<div>
{drawerOpen ? (
Object.keys(parameterSelect).map((key, index) => {
return (
<div>
<FormControl component="fieldset">
<FormLabel className={classes.label} component="legend">
{key}
</FormLabel>
{parameterSelect[key].map((valKey, valIndex) => {
return (
<RadioGroup
aria-label="parameter"
name="parameter"
value={parameterCurrent[key]}//This is where the change should be reflected in the radio button
onChange={(e) => dispatch(
handleParameterChange(e, valKey, index, key)
)}
>
<FormControlLabel
className={classes.formControlparams}
value={valKey}
control={
<Radio
icon={
<RadioButtonUncheckedIcon fontSize="small" />
}
className={clsx(
classes.icon,
classes.checkedIcon
)}
/>
}
label={valKey}
/>
</RadioGroup>
);
})}
</FormControl>
<Divider className={classes.divider} />
</div>
);
})
) : (
<div />
)
}
</div >
)
};
export default Parameter;
What I need to have happen is for value={parameterCurrent[key]} to rerender on handleParameterChange (the handleChange does update the underlying dashboard data, but the radio button doesn't show as being selected until I close the main component and reopen it). I thought I had a solution where I forced a rerender, but because this is a smaller component that is part of a larger one, it was breaking the other parts of the component (i.e. it was re-rendering and preventing the other component from getting state/props from it's reducers). I've been on the internet searching for solutions for 2 days and haven't found anything that works yet. Any help is really apprecaited! TIA!
useSelector() uses strict === reference equality checks by default, not shallow equality.
To use shallow equal check, use this
import { shallowEqual, useSelector } from 'react-redux'
const selectedData = useSelector(selectorReturningObject, shallowEqual)
Read more
Ok, after a lot of iteration, I found a way to make it work (I'm sure this isn't the prettiest or most efficient, but it works, so I'm going with it). I've posted the code with changes below.
I added the updateState and forceUpdate lines when declaring the overall Parameter function:
const Parameter = () => {
let viz = useSelector(state => state.fetchDashboard);
const parameterSelect = useSelector(state => state.fetchParameter)
const parameterCurrent = useSelector(state => state.currentParameter);
const [, updateState] = useState();
const forceUpdate = useCallback(() => updateState({}), []);
const dispatch = useDispatch();
const drawerOpen = useSelector(state => state.filterIconClick);
Then added the forceUpdate() line here:
const handleParameterChange = (event, valKey, index, key) => {
parameterCurrent[key] = event.target.value;
return (
prevState => ({
...prevState,
parameterCurrent: parameterCurrent
}),
() => {
viz
.getWorkbook()
.changeParameterValueAsync(key, valKey)
.then(function () {
//some code describing an alert
});
})
.otherwise(function (err) {
alert(
//some code describing a different alert
);
});
forceUpdate() //added here
}
);
};
Then called forceUpdate in the return statement on the item I wanted to re-render:
<RadioGroup
aria-label="parameter"
name="parameter"
value={forceUpdate, parameterCurrent[key]}//added forceUpdate here
onChange={(e) => dispatch(
handleParameterChange(e, valKey, index, key)
)}
>
I've tested this, and it doesn't break any of the other code. Thanks!
I have a set of buttons in a child component where when clicked set a corresponding state value true or false. I have a useEffect hook in this child component also with dependencies on all these state values so if a button is clicked, this hook then calls setFilter which is passed down as a prop from the parent...
const Filter = ({ setFilter }) => {
const [cycling, setCycling] = useState(true);
const [diy, setDiy] = useState(true);
useEffect(() => {
setFilter({
cycling: cycling,
diy: diy
});
}, [cycling, diy]);
return (
<Fragment>
<Row>
<Col>
<Button block onClick={() => setCycling(!cycling)}>cycling</Button>
</Col>
<Col>
<Button block onClick={() => setdIY(!DIY)}>DIY</Button>
</Col>
</Row>
</Fragment>
);
};
In the parent component I display a list of items. I have two effects in the parent, one which does an initial load of items and then one which fires whenever the filter is changed. I have removed most of the code for brevity but I think the ussue I am having boils down to the fact that on render of my ItemDashboard the filter is being called twice. How can I stop this happening or is there another way I should be looking at this.
const ItemDashboard = () => {
const [filter, setFilter] = useState(null);
useEffect(() => {
console.log('on mount');
}, []);
useEffect(() => {
console.log('filter');
}, [filter]);
return (
<Container>..
<Filter setFilter={setFilter} />
</Container>
);
}
I'm guessing, you're looking for the way to lift state up to common parent.
In order to do that, you may bind event handlers of child components (passed as props) to desired callbacks within their common parent.
The following live-demo demonstrates the concept:
const { render } = ReactDOM,
{ useState } = React
const hobbies = ['cycling', 'DIY', 'hiking']
const ChildList = ({list}) => (
<ul>
{list.map((li,key) => <li {...{key}}>{li}</li>)}
</ul>
)
const ChildFilter = ({onFilter, visibleLabels}) => (
<div>
{
hobbies.map((hobby,key) => (
<label {...{key}}>{hobby}
<input
type="checkbox"
value={hobby}
checked={visibleLabels.includes(hobby)}
onChange={({target:{value,checked}}) => onFilter(value, checked)}
/>
</label>))
}
</div>
)
const Parent = () => {
const [visibleHobbies, setVisibleHobbies] = useState(hobbies),
onChangeVisibility = (hobby,visible) => {
!visible ?
setVisibleHobbies(visibleHobbies.filter(h => h != hobby)) :
setVisibleHobbies([...visibleHobbies, hobby])
}
return (
<div>
<ChildList list={visibleHobbies} />
<ChildFilter onFilter={onChangeVisibility} visibleLabels={visibleHobbies} />
</div>
)
}
render (
<Parent />,
document.getElementById('root')
)
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.12.0/umd/react.production.min.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.11.0/umd/react-dom.production.min.js"></script><div id="root"></div>
Yes, you can, useEffect in child component which depends on the state is also how you typically implement a component which is controlled & uncontrolled:
const NOOP = () => {};
// Filter
const Child = ({ onChange = NOOP }) => {
const [counter, setCounter] = useState(0);
useEffect(() => {
onChange(counter);
}, [counter, onChange]);
const onClick = () => setCounter(c => c + 1);
return (
<div>
<div>{counter}</div>
<button onClick={onClick}>Increase</button>
</div>
);
};
// ItemDashboard
const Parent = () => {
const [value, setState] = useState(null);
useEffect(() => {
console.log(value);
}, [value]);
return <Child onChange={setState} />;
};
I have a event when you resize the window will show desktop sidebar or mobile sidebar. if window is less than But there are variables that aren't updated immediately to show sidebar if I'm in desktop window, I could that with class
I've created a sandbox https://codesandbox.io/s/sidebar-hooks-8oefi
to see the code, I have the class component in App_class.js which if I replace in App it works, but with hooks (App_hooks.js file, by default in App.js) I can't make it works
Thanks for your attention. I’m looking forward to your reply.
with class I could do that using:
if (isMobile !== wasMobile) {
this.setState({
isOpen: !isMobile
});
}
const App = props => {
//minicomponent to update width
const useListenResize = () => {
const [isOpen, setOpen] = useState(false);
const [isMobile, setMobile] = useState(true);
//const [previousWidth, setPreviousWidth] = useState( -1 );
let previousWidth = -1;
const updateWidth = () => {
const width = window.innerWidth;
const widthLimit = 576;
let newValueMobile = width <= widthLimit;
setMobile(isMobile => newValueMobile);
const wasMobile = previousWidth <= widthLimit;
if (isMobile !== wasMobile) {
setOpen(isOpen => !isMobile);
}
//setPreviousWidth( width );
previousWidth = width;
};
useEffect(() => {
updateWidth();
window.addEventListener("resize", updateWidth);
return () => {
window.removeEventListener("resize", updateWidth);
};
// eslint-disable-next-line
}, []);
return isOpen;
};
const [isOpen, setOpen] = useState(useListenResize());
const toggle = () => {
setOpen(!isOpen);
};
return (
<div className="App wrapper">
<SideBar toggle={toggle} isOpen={isOpen} />
<Container fluid className={classNames("content", { "is-open": isOpen })}>
<Dashboard toggle={toggle} isOpen={isOpen} />
</Container>
</div>
);
};
export default App;
with setState didn't work
The issue is after setting isMobile value here,
setMobile(isMobile => newValueMobile);
You are immediately refering that value,
if (isMobile !== wasMobile) {
setOpen(isOpen => !isMobile);
}
Due to async nature of setState, your are getting previous value of isMobile here all the times.
To make this work you need to make some change to your code.
You are directly mutating previousWidth value, you should have previousWidth in a state and use setter function to change the value.
const [previousWidth, setPreviousWidth] = useState(-1);
setPreviousWidth(width); //setter function
You cannot get value immediately after setState. You should use another useEffect with isMobile and previousWidth as dependency array.
useEffect(() => {
const wasMobile = previousWidth <= widthLimit;
if (isMobile !== wasMobile) {
setOpen(isOpen => !isMobile);
}
}, [isMobile, previousWidth]);
Demo
Since updateWidth is registered once on component mount with useEffect, then it will refer to a stale state (isMobile), which is always true, therefore, setOpen(isOpen => !isMobile) will never work.
EDIT: The following code illustrates a simpler version of your issue:
const Counter = () => {
const [count, setCount] = useState(0)
const logCount = () => {
console.log(count);
}
useEffect(() => {
window.addEventListener('resize', logCount);
}, [])
return (
<div>
<p>You clicked {count} times</p>
<button onClick={() => setCount(count + 1)}>
Click me
</button>
</div>
)
}
If you run this code, you will notice that even if you change the value of count by clicking on the button, you will always get the initial value when resizing the browser (check the console), and that's because logCount refer to a state that was obtained at the moment it was defined.
#ravibagul91 answer works, because it access the state from useEffect, and not from the event handler.
You may wanna check: React hooks behaviour with event listener and Why am I seeing stale props or state inside my function?, it will give you a better idea of what's going on.