Selecting multiple DOM elements in React - reactjs

I made simple React component with some images that I want to animate as they are shown in viewport. To use getboundingclientrect() method I have to pass an element so I used js querySelectorAll('img') in componentDidMount() where my scrollEventListener is. It doesn't feel like the right way to go (although works fine). Is there more 'Reactish' solve for that problem?

Yes, you need to use Refs.
With React, usually you shouldn't have to use native dom selectors. By using refs it stays in the React scope and you'll have a more robust workflow.

Related

Getting elements by className in a React Function Component

For class Components in React, I could use
ReactDOM.findDOMNode(<instance-of-outermost-component>).getElementsByClassName('snap')
to get all the elements with className snap, but It doesn’t work with function components. How can I get all the elements with the same Classname in function components?
You should not really be accessing the DOM like that with React- unless you are using it within a testing framework. But even then you would not be accessing the DOM through ReactDom.
What are you trying to actually do when accessing the classes like that?
To apply changes in React you would want to be using state and then conditionally apply these to components. It seems like you are trying to apply a practice common in vanilla javascript development or even something like jQuery.
I think you would benefit from going through this demo of how state can be used: react state tutorial

How to pass data from stencil component to other component in react

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.

Is it possible to access DOM and manipulate it out of render method in react?

I want to use react as a js library injected into my html page. like JQuery, to access DOM and manipulate it. In Vue.js we can do this but in react I doubt it works. I can't access DOM out of react Component and render method.I want a solution to access elements out of render method
You can make use of ref callback to access the dom element in react, which is what React Docs recommend to follow..
DOCS
You can use plain native JavaScript, for eg. document.querySelector() in any lifecycle function of React as well as in render().
Can you give an example of what you're trying to do exactly?

Is there a way in React to find all tags or classes of a certain type?

I just want to do something simple like:
ReactDOM.find('img')
I can't seem to find anything in the documentation that does this. Do I just need to use jQuery? In my componentDidMount method, I want to add a listener to all img tags.
React does not have wrappers for convenient DOM access / DOM manipulation similar to jQuery because React recommends against having to access the DOM at all.
The DOM should be treated just as a rendering layer, not as a data store - your application state should entirely reside in javascript. Hence you never need to either access the DOM nor query it.

Issue with UI event when rendering component inside a web component shadow DOM

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.

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