Building a performance sensitive Redux app that needs to listen to scroll/mouse events throughout a user session.
Plain english implementation would be:
"When component A is in the user's viewport, dispatch FOO action"
From my understanding, the function calculateViewPort + the comparison checking would need to be conducted in the store on every scroll event.
This seems excessive and slow (haven't tested it yet).
Is there another implementation or approach that I have not yet considered?
I was thinking about using something like RxJS for Redux, but want to consider the tradeoff between bringing in a new library for performance and solving it with my existing toolkit.
If there's a saga approach, I'm more open to that too.
There is a InfiniteScroll component. You can refer this and implement in your way or you can use as it is.
Note: this component is not using the redux-saga.
It's better to go with redux-saga as you would take only the response which comes from the latest api call (last mouse scroll) with takeLatest effect.
React Visibility Sensor might be a good choice here. You can wrap the components in VisibilitySensor component and dispatch an action whenever it is on window viewport.
import React from 'react'
import { connect } from 'react-redux'
import VisibilitySensor from 'react-visibility-sensor'
import CUSTOM_ACTION from 'your-actions'
const CustomComponent = (noticeMe, ...children) => {
const handleChange = (isVisible) => { if (isVisible) { noticeMe(); } }
return <VisibilitySensor>{children}</VisibilitySensor>
}
export connect({}, {
noticeMe: () => dispatch(CUSTOM_ACTION)
})(CustomComponent)
Related
I'm new to Next.js and I'm using it to perform server side rendering on the landing page.
The landing page has: 1 generic component that's the same to every user and 1 component that is specific for each user.
Is it possible to perform server side rendering on the generic component, and client side rendering on the specific one?
Thank you.
Yes, you can do client-rendering for any component in your hierarchy. Client rendering usually means that when the component first renders, it fires off some asynchronous request for data (from an API, etc).
In your SSR page, just have your user-specific component not render anything on the initial render (except maybe some loading UI). Then include a useEffect hook that triggers the API call and sets state (local or global state as appropriate) which will trigger your component to re-render with the user-specific data.
During SSR, only the loading state will render. As soon as the component is mounted, the useEffect will trigger and the user-specific data will load and the component will re-render.
Overly simplistic example:
const UserGreeting = () => {
const [name, setName] = setState();
useEffect(() => {
getUserNameAsync().then((data) => {
setName(data.name);
})
}, [setName])
if (!name) {
return <div>...</div>
}
return (
<div>Welcome, {name}</div>
)
}
To make a page both dynamic and static at the same time is possible.
the solution for dynamic: you have to use react useState then useEffect to send the request after unloading fishing on the client side
but first must use next.js api getStaticProps() make the page static user's first visit
In a Next.js app (full-featured, not next export) that uses React Context for state management and the file-system based router, how can you implement advanced routing?
I want to have preconditions for certain pages, so for instance if you try to load /foo but the Context doesn't have a given property set correctly, it'll route you to /bar.
The actual logic is complex and varies by page, so I'm looking for an approach that's easy to maintain.
Note that these preconditions are not authorization-related, so they do not need to be enforced server-side. It's more like "you need to fill out this form before you can go here."
The use of Context imposes some constraints:
Context must be accessed in a React component or in a custom Hook
Using a custom server for routing is not an option, as that would lose the Context - it has to use client-side routing
The current Context has to be checked (I tried decorating useRouter, but if the Context was changed right before router.push, the custom Hook saw the old values)
Update: It's also good to avoid a flash when the page loads before rerouting happens, so a side goal is to return a loading indicator component in that case.
I believe you can create a HOC and wrapped every pages with you HOC that takes arguments e.g. { redirects: '/foo' }
// pages/bar.tsx
const Page = () => {...}
export default RouteHOC({ redirects: '/foo' })(Page)
the HOC file will be something like this
// hoc/RouteHOC.tsx
const RouteHOC = ({ redirects }) => (WrappedComponent) => {
// you can do your logic here with the context.. even filling up a form here
// too also can.. (like returning a modal first before the real Component).
// useEffect work here too..
const { replace } = useRouter()
// then after you want to replace the url with other page
replace(redirects)
return WrappedComponent
}
This is pretty okay to be maintainable I think. You just create all the logic in HOC and when you want to update the logic - you just have to edit it in 1 file.
Well this is one option I can think of when reading your question - sorry if I misunderstood it in any way. There will always be a better way out there as we all know we can improve and adapt to new situation every seconds :D. Cheers 🥂!!
You can do this.
const Component = () => {
const example = useExample()
return <div id='routes'>
<a href='/example1'>Example 1</a>
{example.whatever && <a href='/example2'>Example 1</a>}
</div>
}
https://developer.wordpress.org/block-editor/reference-guides/components/dimension-control/
Docs says that DimensionControl is used by wp.blockEditor. But I haven't DimensionControl in wp.blockEditor or wp.components or wp.element. Is this Component enabled by default or is needed to be enabled manually?
The dimension control component is now inside the #wordpress-components library or package.
// https://github.com/WordPress/gutenberg/tree/trunk/packages/components/src
You might be able to import it like this.
import { DimensionControl } from '#wordpress/components';
Or
import { __experimentalDimensionControl } from '#wordpress/components';
And apparently it is not stable yet, so you may want to wait before actually using it on production.
I have a component which is connected to global store and getting some data from the global store. from some portion of this data is sent to another component via props and inside that component i have generated required jsx based on data. Also inside the child component mapdispatchtoprops is also used and it is also connected to global store as well.
The problem case scenario is child component re-renders depends upon the global store data.
The key for global store is like -
foods : {
'list' : '',
's' : '',
fetching : 0,
slist : '',
category : '',
cproducts : ''
}
I guess what happening is the child component is re-rendered 7 times because the number of keys inside global store for foods is 7. if anyone is interested he/she can share his/her views
Components have a render method which returns the JSX markup that it renders to the DOM. For change detection, React use a local state, which is only local to a component, when the state changes the component and its children are re-rendered to update the UI of the changed state.
A quote from the React documentation:
These components must not retain internal state, do not have backing instances, and do not have the component lifecycle methods. They are pure functional transforms of their input, with zero boilerplate. However, you may still specify .propTypes and .defaultProps by setting them as properties on the function, just as you would set them on an ES6 class.
PURE COMPONENT is one of the most significant ways to optimize React applications. The usage of Pure Component gives a considerable increase in performance because it reduces the number of render operation in the application.
So change your app to be like this
import React, {PureComponent} from 'react';
class Sample extends PureComponent {
render() {
return (
<div>your structure here</div>
)
}
}
export default Sample;
Please read more on react PureComponent. here
I realize this is a fundamental question that may have been answered before, but I'm looking for a definitive answer, with perhaps some reasoning, as I've not quite found one that convinces me that there is better/best/preferred way to do handle this.
Scenario: A dashboard component receives redux state via connect. Some of the data is shared across the dashboard and its children. Some of the data is specific to the dashboard's children.
Question: Should I always pass the props down to the child components (something) like the below, or should I always connect the child components to redux and read the needed data directly from redux state?
import React, { Component } from "react";
import { connect } from "react-redux";
import ChildOne from ".ChildOne";
import ChildTwo from ".ChildTwo";
class DashboardExample extends Component {
render() {
const { sharedData, childOneData, childTwoData } = this.props
return (
<div>
<h1>{sharedData.selectedDate}</h1>
<ChildOne sharedData={sharedData} childOneData={childOneData} />
<ChildTwo sharedData={sharedData} childTwoData={childTwoData} />
</div>
);
}
}
const mapStateToProps = state => ({
sharedData: state.dashboardData,
childOneData: state.childOneSpecificData,
childTwoData: state.childTwoSpecificData,
});
export default connect(mapStateToProps)(DashboardExample);
As Dan Abramov said, it’s nice to have a division between Presentational Components and Container Components.
Presentational Components
Are concerned with how things look.
May contain both presentational and container components** inside,
and usually have some DOM markup and styles of their own.
Often allow containment via this.props.children.
Have no dependencies on the rest of the app, such as redux actions
or stores.
Don’t specify how the data is loaded or mutated.
Receive data and callbacks exclusively via props.
Rarely have their own state (when they do, it’s UI state rather than
data).
Are written as functional components unless they need state,
lifecycle hooks, or performance optimizations.
Container Components
Are concerned with how things work.
May contain both presentational and container components** inside but usually don’t have any DOM markup of their own except for some wrapping divs, and never have any styles.
Provide the data and behavior to presentational or other container components.
Call redux actions and provide these as callbacks to the presentational components.
Are often stateful, as they tend to serve as data sources.
Are usually generated using higher order components such as connect() from React Redux, createContainer() from Relay, or Container.create() from Flux Utils, rather than written by hand.
source post
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Specific answer to your question:
I find it helpful to try and stick with the principles stated above. It makes your code easy to reason about and it helps to separate concerns (Views / Business logic).
But, if you find yourself writing spaguetti props to stick to it, or if it doesn’t feel natural in a specific piece of code, just connect your Presentational Component.