I am creating a web app with React which has a form component, uses Formik field and Yup schema for validation. I am also using Redux to capture some form input to render some other component. Everything works ok, but the initial render time is too slow. But once loaded it works fine and 2nd, 3rd refresh is correct very little render time. I am using create react app.
What is the solution? What should I look for? Chrome Dev Tools saying long function chain is main problem. I don't know where is this chain.
Sincerely,
I am out of clue here, component composition and image optimization is key, it is being said in multiple blogs, but not sure in this case.
Related
I have created one search component using stencil and I'm integrating this stencil codebase with my react application via cdn link. I'm displaying the search component(which was created in stencil) as below in my react codebase :
<custom-search placeholder="Search"></custom-search>
The search component contains a search icon. I need to pass the text in search input field to my react code on click of this icon. How can this be achieved?
Unfortunately I haven't integrate Stencil JS component with React, but passing string data to web component should be working without too much hassle. Do you know if your React app can properly recognize your custom-search component? If not, then you might want to take a look at a link to Stencil JS official document of integrating Stencil JS component to React and make sure component get properly loaded and integrated.
If you know for sure you load the component then not sure why your placeholder is not set within your component - it is just a string after all. Maybe post the custom-search component code, as there might be issue with that (i.e. component lifecycle event you are using might not be doing what you expect to do)
Could you clarify the actual problem, please? :)
Does the component not get rendered, or are you unable to achieve communication from custom-search to the React app?
If the latter is the case, you might want to implement a Custom Event on the Stencil component, to communicate changes back to the consuming app.
As #tomokat mentioned, you should follow the official Stencil React integration docs. This is required, since React cannot handle Custom Events natively, and requires some help from the dev.
Edit: Sorry, I got confused by the first answer. Your title is quite clear, though. If you can show some example code of the component and the React integration, we could probably help in a better way.
We will be doing our first project using React.
It will not be a Single Page App, but a Multiple Page App.
What I'm trying to figure out at the moment is : what's the difference between a component and an app.
If I only use components, can I still use Redux to have some state management on the current page ? Or do I need an app for this ?
Thanks for the information you can bring !
THoma
There is no special object called "React App". React Components build an "React App" by coming together.
But React Components are formed like tree structure. That means each component have a parent component so you can create a React Component that named "App" and can put another components inside it.
You don't need redux for state management in React Components.
I hope the answers have helped.
Your app may contains a single component and still it will be a react App. If you are using multiple components in a page you can still use react-redux. Redux is basically a container for your states and let suppose you need some state from one component to be consumed in another, Redux provide you a mechanism to make the communication efficient and predictable.
You can also look at the React Context APIs as an alternate to Redux.
An app is simply a component that holds the root of the work you are trying to do. For example an App may have the navigation menu, testimonials, adverts, content, login avitar etc.
If you are making a single App per page (For example a testimonial) then you would still have a SPA. For example, adding testimonials, searching, editing.
You should only use Redux if you are using a SPA with lots of different parts with data in common. If you are making a one-app-per-page and there is no cross over in data then you can simply using Reacts State/Props to hold your data.
Redux is good, but it forces you into a complex path your should try to avoid. If you find yourself wanting data from different domains (customers address and a list of testimonials) then you should use Redux.
If this is a new applications (green) then I strongly recommend you build the whole thing within a SPA using React-Router to control components. you can use frameworks like Next.JS to ensure the site remains small in size (dynamically loading script only when required).
I am using React-Redux-Form and React-Bootstrap on client side of application.
I'm stuck on how to testing my components. I have made a small project on github with one of my components named LoginModal:
https://github.com/DmitryIvanovIAMM/react-redux-form-login-test/blob/master/src/tests/Foo-test.js.
To start testing, I am following this tutorial https://www.codementor.io/vijayst/unit-testing-react-components-jest-or-enzyme-du1087lh8.
But when I try to .find() button in my rendered component, the result is an array of length zero. So I can't simulate its behaviour. I try find it (button) several different way but unsuccessful. Please, your suggestion.
This issue is with the rendering of Modal component that is part of #react-bootstrap. There is a discussion about it on https://github.com/react-bootstrap/react-bootstrap/issues/876.
The alternative is to use ReactModal from react-modal. Testing it is described on http://remarkablemark.org/blog/2017/05/17/testing-react-modal/
Is there any way to get logs of which all React components get rendered or rerendered when any event/action is performed. I just want to check whether any unwanted React component is getting rerendered. I know we could achieve this by adding consoles in render function, componentWillReceiveProps or componentWillUpdate. But I have number of components in my webapp. Adding console statements in each component would be a mess. Is there a better way?
A nice option is to visualise React components in the chrome timeline. This lets you see which components exactly get mounted, updated, and unmounted and how much time they take relative to each other. That feature was added as part of the release of React 15.4.0. You can take a look at the official blogpost to get a better insight, but summing up, those are the steps to get it up and running:
Load your app with ?react_perf in the query string (for example, http://localhost:3000/?react_perf).
Open the Chrome DevTools Timeline tab and press Record.
Perform the actions you want to profile. Don't record more than 20 seconds or Chrome might hang.
Stop recording.
React events will be grouped under the User Timing label.
After that, you will get a cool visual representation of mounting, updating and unmounting of your different components over time
In addition to rauliyohmc answer. Profiling tool he described is really helpful and powerful, but if your task is just checking if there are unnecessary re-renders (i.e. ones which did not lead to DOM changes) you can use nice and simple react-addons-perf tool. It has printWasted method which will provide you info about wasted re-renders.
I'm facing some issues when rendering a React component into the shadow DOM of a webcomponent.
I wrote a small piece of code to turn a React component into a webcomponent, but I want to render the
React component inside the shadow DOM of the webcomponent. But in that case, it seems that React is not able to catch UI events (click, keyPress, etc ...) anymore.
Let's take an example, let say that I have a first webcomponent <awesome-timer /> that render the React component inside the webcomponent node, and another webcomponent <less-awesome-timer /> that render the React component inside the shadow DOM of the webcomponent.
Both webcomponents use the same React component. However the one rendered inside the shadow DOM does not work, because click events on the button of the timer component does not trigger the bound function.
I guess React is not designed to handle such case, but I'd love to get more details about it.
The code of the example is available here : https://gist.github.com/mathieuancelin/cca14d31184bf4468bc1
Does anyone have an idea about it ?
I know this is kinda late but, I believe your issue when you pass any attributes to a web component they instantly become strings Because that's all you can pass to a web component. Now of course you can convert or cast them back to there original data type, except functions because once stringified they loose there scoping, lexical and all.
Now to your main question, you are were trying to pass you child element through the Main web components slot. Now you have to remember that once you pass anything to a web component you now have to use the webs components methods and return types to manage whatever you pass. So yes passing react into a web component will not work they you expect.
You will need to go back to whatever tool you use to build your web component and deal with the slot logic there. Since this is a very old post as are web components. You might not have had access to the modern web component build tool's we have today. I found Stenicl allows you to build and manage your web components in Typescript.
A good option is to change your pattern a little bit and just return web components from your react app.
Or you can use another really cool to call Lit-HTML or Lit-element. I believe they may have combined there core libraries. Anyway these tool will allow you to combine Reactjs and web components where lit-html gives you access to methods simial to Reactjs's life cycle methods. Anyway some good stuff to check out if your stuck at this point.