js - Redux(Redux Toolkit, Redux Persist, Thunk, Reselect) - CSS in JS (styled-components) - Material. Hi! This seems similar to this topic but I can't tell if it's quite the same, I'd love any input I could get. # react # redux # reduxsaga More on this series: Part I ⋮ Part III For this part we’ll be focusing on the component setup, and the srolling part and fetching data when the scroll is at the bottom. Hi! This seems similar to this topic but I can't tell if it's quite the same, I'd love any input I could get. Infinite Scroll in React is a highly requested app feature that can be achieved in several ways. Row 0. The "Create Action" Lesson is part of the full, Advanced Redux with Redux Toolkit course featured in this preview video. Issue I am getting different behavior when using arm-none-eabi-ld -T t. Dani-Boy92 on Oct 1, 2021 I am trying to implement a simple infinite scroll in RTK Query in the form of a slider. Viewed 2 times. Hi, I'm a Front-end developer. Redux Toolkit. I'm implementing an infinite list component, and I want to be able to pass in generic queries that have paginated responses through a prop so that all of the pagination logic can be encapsulated to that single component, regardless of what the paginated items happen to be. Redux Toolkit is our recommended approach for writing Redux logic. Refresh the. With CodeSandbox, you can easily learn how mescalito has skilfully integrated different packages and frameworks. SheCodes Tools Free coding tools for developers SheCodes Connect Connect with SheCodes Alumni SheCodes Radio Curated tracks to help you keep on track, 24/7 SheCodes Challenges Coding challenges for the SheCodes Community. Online retailers like this pattern for loading products as it allows a user to seamlessly browse through every product available within a category, without having to pause every so often and wait for the next page to load. Viewed 2 times. Redux Toolkit is our recommended approach for writing Redux logic. The third and final application uses the same paginated API and uses the same Redux structure. Infinite Scroll - A scheduler which contains a year's worth of events and may be. { useDispatch } from 'react-redux'; import * as R from 'ramda'; import { ApiEndpointQuery } from '@reduxjs/toolkit/dist/query/core/module' . React Projects React Tutorials Redux Toolkit Project YouTube Clone with React, Redux Toolkit, Typescript, Tailwind CSS . I'm implementing an infinite list component, and I want to be able to pass in generic queries that have paginated responses through a prop so that all of the pagination logic can be encapsulated to that single component, regardless of what the paginated items happen to be. I found that Stack Overflow discussion with a basic first implementation. Infinite Scrolling is a way to implement pagination in mobile devices. I have used great example from github discussion https://github. Hi! This seems similar to this topic but I can't tell if it's quite the same, I'd love any input I could get. With that component, we can . Applying useRef. There are multiple types of "infinite" APIs: paginated, cursor-based, and offset-based - and mixes between those. State management with. RTK Query is intended to make data fetching and caching with Redux as easy as possible. Infinite Scrolling is a way to implement pagination in mobile devices. Now, they’ve added “the newest member of the Redux family”, RTK Query. It is a helper method to generate a store slice. It allows you to define a set of "endpoints" that describe how to retrieve data from backend APIs and other async sources, including the configuration of how to fetch and transform that data. NODE_ENV !== 'production' 구문을 리듀서에 추가하여 설정할 수 있다. For this part we'll be focusing on the component setup, and the srolling part and fetching data when the scroll is at the bottom. 我正在使用此程序包https: github. We have configured the basic API function from where we will call the API. To address this, the Redux team has released Redux Toolkit (RTK): an opinionated toolset for writing Redux applications. A potential pitfall when combining this with pagination is that your paginated query may only provide a partial list at any given time, and hence not provide tags for entity IDs that fall on pages. An example showing how to implement Load More Infinite Scroll in React Query. When I set payload to redux/tookit state , My browser scroll to up !! I was check out a redux state action so It does. I came across situations where I had to make GET requests, So I recently started using Redux-Thunk (before this I used useEffect but, as it’s not a standard way to handle async functions, when using redux. Todos Run the Todos example:. Hi! This seems similar to this topic but I can't tell if it's quite the same, I'd love any input I could get. 🖐 Every day I learn something new and enjoy what I do. 9+ there's a better recommended way of handling infinite scrolling. Online retailers like this pattern for loading products as it allows a user to seamlessly browse through every product available within a category, without having to pause every so often and wait for the next page to load. Implementing infinite scroll would be super easy for us. What if discovering the best White WordPress templates wasn’t so easy? ⚡️ Do you want a quick response? The Publisher theme is a powerful, mobile-friendly plugin that provides. What if discovering the best White WordPress templates wasn’t so easy? ⚡️ Do you want a quick response? The Publisher theme is a powerful, mobile-friendly plugin that provides. 0 #2930 Unanswered jnavb asked this question in Q&A jnavb on Nov 22, 2022 For infinite scroll I'm currently using one of the @phryneas solution for infinite scroll that was answered in this long thread #1163 (comment). types of morphology in biology; proverbs 31 single mother; part time jobs in kuwait sharq. What if discovering the best White WordPress templates wasn’t so easy? ⚡️ Do you want a quick response? The Publisher theme is a powerful, mobile-friendly plugin that provides. This React full tutorial provides two examples of creating an infinite scroll: 1) with. To illustrate this, I've created a working example on CodeSandbox. Since RTK Query builds on top of Redux Toolkit and React-Redux, the added size varies depending on whether you are already using those in your app. Product comparison page build using React + Redux + Bootstrap + SASS. reduxjs/redux-toolkit This Sandbox is in sync with masteron GitHub. Implementing infinite scroll would be super easy for us. Vulnerability DB; Code Checker; Snyk Learn; Blog; Sign Up. Infinite Scrolling with React and Redux-Saga. Redux Toolkit's createEntityAdapter API provides a standardized way to store your data in a slice by taking a collection of items and putting them into the shape of { ids: [], entities: {} }. WPF DataGrid Control Introduction Since. Hi! This seems similar to this topic but I can't tell if it's quite the same, I'd love any input I could get. 1 Because you set on every dispatch a different payload value, your previous array disappears. Infinite scrolling using redux and sagas, Part II. Infinite loading is a pattern that is very common in ecommerce applications. React Query is often described as the missing piece in the React ecosystem. usePosts custom hook. js - Redux(Redux Toolkit, Redux Persist, Thunk, Reselect) - CSS in JS (styled-components) - Material. Using this you can easily implement infinite scroll. Modified today. 0 #2930 Unanswered jnavb asked this question in Q&A jnavb on Nov 22, 2022 For infinite scroll I'm currently using one of the @phryneas solution for infinite scroll that was answered in this long thread #1163 (comment). 9+ there's a better recommended way of handling infinite scrolling. Asked today. For my final project with the FlatIron School, I developed Osiris, . Asked today. I'm implementing an infinite list component, and I want to be able to pass in generic queries that have paginated responses through a prop so that all of the pagination logic can be encapsulated to that single component, regardless of what the paginated items happen to be. 1 componentDidMount() { 2 this. API communication also won’t be included, however, the Hook can be extended to include it. usePosts custom hook. We can create, retrieve, update, delete items. However, structuring the Firestore, Redux, Redux-Saga, and React code to maximize readability and maintainability was difficult. Infinite scrolling using redux and sagas, Part I. When I set payload to redux/tookit state , My browser scroll to up !! I was check out a redux state action so It does. Get Started. It is a helper method to generate a store slice. Redux Toolkit. Row 1. I found that Stack Overflow discussion with a basic first implementation. The infinite scrolling feature may seem like an elegant replacement for pagination. Using the “Infinite Scrolling” Method to Fetch API Data in ReactJS | by crashdaddy | Medium 500 Apologies, but something went wrong on our end. It allows you to define a set of "endpoints" that describe how to retrieve data from backend APIs and other async sources, including the configuration of how to fetch and transform that data. Hi! This seems similar to this topic but I can't tell if it's quite the same, I'd love any input I could get. Latest version: 6. Valheim Genshin Impact Minecraft Pokimane Halo Infinite Call of Duty: Warzone Path of Exile Hollow Knight: Silksong Escape from Tarkov Watch Dogs: Legion. push 它成功运行loadMore函数，但不扩展当前列表. Infinite scroll with RTK (redux-toolkit) Ask Question. Infinite scrolling using redux and sagas, Part I. Building Real World, Production Quality Apps with React & Redux. Whit this adapter you can easily manage arrays, you can add, modify, update or remove items from the array. Modified today. Infinite Scroll Product search Data fetching through axios Theme customization options Multiple Header Varations Multiple Footer Varations Multiple Blog Varations Total 100+ Pages Mega Menu Integrated Mobile Optimized Design Amazing Property Zoom Offcanvas Menu Supported RTL Languages Supported Unlimited Colors & Layouts. October 14, 2019 - 7 min read. Post component and forwardRef. You give the view component the entire list of model objects, but it only renders the DOM elements for the objects that would be shown in the viewport of the view component. This React full tutorial provides two examples of creating an infinite scroll: 1) with. Skip to the reply #1163 (reply in thread). React Example – Product Compare Page 🎉 🎆. I came across situations where I had to make GET requests, So I recently started using Redux-Thunk (before this I used useEffect but, as it’s not a standard way to handle async functions, when using redux. We have configured the basic API function from where we will call the API. Modified today. List of infinite scroll component/hook libraries:. Modified today. Setting up React Query; Pagination with useQuery and keepPreviousData; Infinite Scroll with useInfiniteQuery;. It is designed to simplify common cases for loading data in a web application, eliminating the need to hand-write data fetching & caching logic yourself. devTools: process. Upon scrolling to the bottom of the page, we then fetch the next 5 Posts. It, however, triggers the pagination using scroll. I came across situations where I had to make GET requests, So I recently started using Redux-Thunk (before this I used useEffect but, as it’s not a standard way to handle async functions, when using redux. For my final project with the FlatIron School, I developed Osiris, . But not able to achieve the. There are multiple types of "infinite" APIs: paginated,. It would be utterly useless for 90% of users. Share Improve this answer Follow edited Dec 19, 2022 at 13:20. Implementing infinite scroll would be super easy for us. Intersection Observable API를 이용 . Infinite scrolling using redux and sagas, Part I. We have configured the basic API function from where we will call the API. Infinite scrolling with the help of FlatList. There are a handful of situations that you may want to do this, but some very common use cases are: User hovers over a navigation element. RTK Query is intended to make data fetching and caching with Redux as easy as possible. Redux saga is an awesome library to handle side effects, basically here we use the call effect to execute a promise, which in our case is the request to the endpoint (we’ll define those functions later), everything is inside the try catch because given the promise result we either going to display an error message or a success response, by using. Advisor; JavaScript packages; redux-infinite-scroll; redux-infinite-scroll v1. Row 0. DataGrid element represents WPF DataGrid control. o ts. Download the WPF Toolkit - either source or binaries (the toolkit is entirely open source). Infinite Scrolling With React js Tutorial - infinity scroll in React js that fetches data from an API (HTTP GET Request)Download source codehttps://github. CSS / Styling. push 它成功运行loadMore函数，但不扩展当前列表. /reducer'; import Infinite from 'react-infinite'; import InfiniteScroll from 'redux-infinite-scroll';. Viewed 2 times. However, structuring the Firestore, Redux, Redux-Saga, and React code to maximize readability and maintainability was difficult. To create a new React Native app, let's generate a project using the create-react-native-app command-line tool. User hovers over a list element that is a link. Along with this predefined state shape, it generates a set of reducer functions and selectors that know how to work with that data. So, what would be the right way to achieve this. Hey all! First off, great work on RTK Query!. I have a redux slice called . Data Viz. com (Open API) Tailwind (CSS Framework) Axios (Http Request) Features. For this part we'll be focusing on the component setup, and the srolling part and fetching data when the scroll is at the bottom. Infinite Scrolling With React js Tutorial - infinity scroll in React js that fetches data from an API (HTTP GET Request)Download source codehttps://github. 我正在使用此程序包https: github. Infinite scrolling using redux and sagas, Part II. In this article, I'll explain how to create infinite scrolling in your. The official, opinionated, batteries-included toolset for efficient Redux development. Repository url. We have also called the getPhotos () function from the componentDidMount () lifecycle hook, but it will be enough to develop the infinite scroll. 我正在使用此程序包https: github. ld -o t. I have a redux slice called . Repository url. Infinite scrolling is a popular interaction pattern that allows users to continuously load content while scrolling down a page. March 14, 2012 • DataGrid, WPF A data grid usually allows users to reorder, resize, and sort its columns. NODE_ENV !== 'production' 구문을 리듀서에 추가하여 설정할 수 있다. Our component structure will be the following: Provider (React-redux wrapper. Prefetching | Redux Toolkit RTK Query Using RTK Query Prefetching Prefetching The goal of prefetching is to make data fetch before the user navigates to a page or attempts to load some known content. Modified today. 我正在使用此程序包https: github. push 它成功运行loadMore函数，但不扩展当前列表. In June 2021, Redux Toolkit introduced a powerful tool for data fetching and caching called RTK Query. When I set payload to redux/tookit state , My browser scroll to up !! I was check out a redux state action so It does. Redux DevTools Extension. import { createApi } from "@reduxjs/toolkit/query/react";. Infinite scrolling using redux and sagas, Part I. Creating a Hook for infinite scroll Before we get into the details, let’s first outline what the Hook will and will not manage. { createStore, combineReducers,. I have used great example from github discussion https://github. It, however, triggers the pagination using scroll. Hi, I'm a Front-end developer. Now, they’ve added “the newest member of the Redux family”, RTK Query. tsx index. Asked today. There are multiple types of "infinite" APIs: paginated,. What if discovering the best White WordPress templates wasn’t so easy? ⚡️ Do you want a quick response? The Publisher theme is a powerful, mobile-friendly plugin that provides. Mern Stack Projects. Since RTK Query builds on top of Redux Toolkit and React-Redux, the added size . Viewed 2 times. RTK Query is intended to make data fetching and caching with Redux as easy as possible. WPF DataGrid Control Introduction Since. Developer Tools. Post component and forwardRef. Infinite Scroll Product search Data fetching through axios Theme customization options Multiple Header Varations Multiple Footer Varations Multiple Blog Varations Total 100+ Pages Mega Menu Integrated Mobile Optimized Design Amazing Property Zoom Offcanvas Menu Supported RTL Languages Supported Unlimited Colors & Layouts. User hovers over a next pagination. dcurletti / redux-infinite-scroll Public Fork 49 178 Code Issues Pull requests Actions Projects 1 Security Insights master 4 branches 9 tags Code 37 commits dev Css transitions ( #29) 7 years ago dist #21 horizontal scrolling ( #27) 7 years ago. It would work with one type of API and with one type of component. Asked today. WPF DataGrid Control Introduction Since. This has several benefits:. Infinite scroll with RTK (redux-toolkit) Ask Question. Implementing infinite scroll with RTK Query · Discussion #1163 · reduxjs/redux-toolkit. Implementing infinite scroll would be super easy for us. In this tutorial we are going to build a react infinite scroll with pure JavaScript and embed it into a ReactJS component. push 它成功运行loadMore函数，但不扩展当前列表. Firstly, your API needs to support pagination. Asked today. I’ve coded my API in such a way that I’ll have to send a limit and skip queries to get the right. We have configured the basic API function from where we will call the API. Now, the problem here is to get the data from multiple different API to fetch other data. usePosts custom hook. Applying useRef. Infinite scrolling using redux and sagas, Part II. Viewed 2 times. In general there are two approaches to Pagination/ Infinite loading: 1. Incase anyone is here and wondering how they can implement and Infinite Scroll in With Redux Tookit Query and React Native Flatlist. Overall Product Weight: 0. Asked today. Infinite scrolling using redux and sagas, Part I. Firstly, your API needs to support pagination. 👩💻 Technology stack: - HTML5 - CSS3(Flexbox/Grid) - SASS - Javascript (ES6+) - React(React router, Hooks,Context API, React Transition Group) - Next. React Example – Product Compare Page 🎉 🎆. Infinite Scroll With ReactJs & Redux Puzant Bakjejian · Follow 3 min read · Jul 8, 2020 Infinite scroll has been widely used in today's web & mobile apps, it simply loads data as you scroll. 👩💻 Technology stack: - HTML5 - CSS3(Flexbox/Grid) - SASS - Javascript (ES6+) - React(React router, Hooks,Context API, React Transition Group) - Next. grand summoners how to redeem codes
1 API Requests with Redux Toolkit. . Redux toolkit infinite scroll
Infinite scrolling is a popular interaction pattern that allows users to continuously load content while scrolling down a page. Along with this predefined state shape, it generates a set of reducer functions and selectors that know how to work with that data. It allows you to define a set of "endpoints" that describe how to retrieve data from backend APIs and other async sources, including the configuration of how to fetch and transform that data. Important If you are using an element as the scrollable component,. For $69, you can get this theme plus six months of support. Get more work done and save valuable time with essential PDF tools and features: View PDF: • Smooth navigation and fast PDF viewing engine • Single or double-page, continuous scroll, and thumbnails view • Dark Mode for reading in low-light environments • Search, copy, and zoom in on. I found that Stack Overflow discussion with a basic first implementation. Xodo is a trusted PDF reader, editor, and converter for Windows. Developer Tools. js - Redux(Redux Toolkit, Redux Persist, Thunk, Reselect) - CSS in JS (styled-components) - Material. Online retailers like this pattern for loading products as it allows a user to seamlessly browse through every product available within a category, without having to pause every so often and wait for the next page to load. garmin edge 520 won't turn off; fire drill solas requirement; mini asphalt paver for sale. Start using react-infinite-scroll-component in your project by running `npm i react-infinite-scroll-component`. The updateUser action takes a userId parameter and a dispatch parameter, which is provided by Redux Toolkit. "load more" data onto an existing set of data or "infinite scroll". ) PokemonList (Component with scrolling logic and api calls) PokemonListItem (Stateless component just for displaying the pokemon). 👩💻 Technology stack: - HTML5 - CSS3(Flexbox/Grid) - SASS - Javascript (ES6+) - React(React router, Hooks,Context API, React Transition Group) - Next. Now, the problem here is to get the data from multiple different API to fetch other data. Product comparison page build using React + Redux + Bootstrap + SASS. push 它成功运行loadMore函数，但不扩展当前列表. Infinite Scrolling is a way to implement pagination in mobile devices. Learn how to implement infinite scrolling using React with the component state and an onscroll event handler. While working on a React project with Redux-Saga and Firebase, I wanted to add infinite scrolling to improve site performance and user experience. We have also called the getPhotos () function from the componentDidMount () lifecycle hook, but it will be enough to develop the infinite scroll. o ts. help with Redux toolkit actions. There are multiple types of "infinite" APIs: paginated, cursor-based, and offset-based - and mixes between those. Here is my implementation of useInfiniteQuery. Take a look at the entityAdapter. ld -o t. However, I can't get it to run based on the instructions provided. com/RealScout/redux-infinite-scroll在品牌列表上进行无限滚动。 这是我的代码： 容器： import React, { Component } from 'react'; import { connect } from 'react-redux'; import { actions, getBrands } from '. There is a Search bar for finding items by title. Redux Toolkit can replace a series of actions/reducers/constants using its createSlice API. For this part we’ll be focusing on the component setup, and the srolling part and fetching data when the scroll is at the bottom. This example includes tests. It would be utterly useless for 90% of users. Check out a free preview of the full Advanced Redux with Redux Toolkit course: The "Create Reducer" Lesson is part of the full, Advanced Redux with Redux Toolkit course featured in this preview video. Infinite Scroll With ReactJs & Redux | by Puzant Bakjejian | Medium Sign up 500 Apologies, but something went wrong on our end. There are a handful of situations that you may want to do this, but some very common use cases are: User hovers over a navigation element. With the solution you have given and following the map approach, I can basically fetch "infinity". Changing the pageNumber parameter of your query, will automatically fetch new data and concat it with the data that was already in the cache. It would work with one type of API and with one type of component. It does not matter how experienced or high your skill . push 它成功运行loadMore函数，但不扩展当前列表. ) PokemonList (Component with scrolling logic and api calls) PokemonListItem (Stateless component just for displaying the pokemon). Modified 7 months ago. I think it's one of the headaches that hasn't been solved for quite some time. 我正在使用此程序包https: github. types of morphology in biology; proverbs 31 single mother; part time jobs in kuwait sharq. I'm implementing an infinite list component, and I want to be able to pass in generic queries that have paginated responses through a prop so that all of the pagination logic can be encapsulated to that single component, regardless of what the paginated items happen to be. com RealScout redux infinite scroll在品牌列表上进行无限滚动。 这是我的代码： 容器： 减速器： adsbygoogle window. You have to fork to make changesFork Files public src app features mocks App. help with Redux toolkit actions. We have configured the basic API function from where we will call the API. 我正在使用此程序包https: github. There are multiple layout options available on the homepage, including a full-screen option with a horizontal ‘striped’ navigation bar. Issue I have prepared a simple test project at GitHub for my question. I've based my use off the examples given here: https://redux-toolkit. { createStore, combineReducers,. I'm implementing an infinite list component, and I want to be able to pass in generic queries that have paginated responses through a prop so that all of the pagination logic can be encapsulated to that single component, regardless of what the paginated items happen to be. For $69, you can get this theme plus six months of support. 我正在使用此程序包https: github. React infinite scroll component designed for a Redux data-flow. I'm implementing an infinite list component, and I want to be able to pass in generic queries that have paginated responses through a prop so that all of the pagination logic can be encapsulated to that single component, regardless of what the paginated items happen to be. The infinite list is a very common pattern to display a list of results. In June 2021, Redux Toolkit introduced a powerful tool for data fetching and caching called RTK Query. const { status, data, error, isFetching, isFetchingMore, fetchMore, canFetchMore } = useInfiniteQuery('fetchPokemons', fetchPokemons, { . 🖐 Every day I learn something new and enjoy what I do. Browse By Category; React; React Native; Best. Asked today. Inside the updateUser action, we make. Whit this adapter you can easily manage arrays, you can add, modify, update or remove items from the array. This tool helps. Modified today. Creating a Hook for infinite scroll Before we get into the details, let’s first outline what the Hook will and will not manage. Please help me out with this. It, however, triggers the pagination using scroll events and displays all of the item through the current page (instead of just the items in the current page). Problem with the code is that you make the same request, there is no paging? The second problem is that you assume data resolves in the same order as the requests were made but this is not the case. Infinite scrolling. 1) you fetch first photos and set the components initial state 2) after you scroll to the waypoint it fires a method which makes another request to the api, constructs new photos array (appending newly fetched photos) and (!) call setState with the new photos array. Start using react-infinite-scroll-component in your project by running `npm i react-infinite-scroll-component`. It is a helper method to generate a store slice. Viewed 2 times. Example 1 component. 9+ there's a better recommended way of handling infinite scrolling. When I set payload to redux/tookit state , My browser scroll to up !! I was check out a redux state action so It does. Now, they’ve added “the newest member of the Redux family”, RTK Query. Redux Toolkit is our recommended approach for writing Redux logic. When I set payload to redux/tookit state , My browser scroll to up !! I was check out a redux state action so It does. Issue After many attempts, and trying many solutions that I could find on stackoverflow or. Intersection Observable API를 이용 . Viewed 2 times. Infinite scrolling. We send the query Params along with an extra page number query param this page number param change as we scroll or. Since RTK Query builds on top of Redux Toolkit and React-Redux, the added size varies depending on whether you are already using those in your app. 🖐 Every day I learn something new and enjoy what I do. So, what would be the right way to achieve this. Infinite Scroll With ReactJs & Redux | by Puzant Bakjejian | Medium Sign up 500 Apologies, but something went wrong on our end. Date formatting. Viewed 2k times. js - Redux(Redux Toolkit, Redux Persist, Thunk, Reselect) - CSS in JS (styled-components) - Material. However, I can't get it to run based on the instructions provided. With CodeSandbox, you can easily learn how mescalito has skilfully integrated different packages and frameworks. Basic List. Using the “Infinite Scrolling” Method to Fetch API Data in ReactJS Not Shown: Directory Structure F or today’s fun adventure we’ll be using ReactJS to fetch data from an API and output that. It would be utterly useless for 90% of users. com/RealScout/redux-infinite-scroll在品牌列表上进行无限滚动。 这是我的代码： 容器： import React, { Component } from 'react'; import { connect } from 'react-redux'; import { actions, getBrands } from '. Check out a free preview of the full Advanced Redux with Redux Toolkit course: The "Create Reducer" Lesson is part of the full, Advanced Redux with Redux Toolkit course featured in this preview video. 👩💻 Technology stack: - HTML5 - CSS3(Flexbox/Grid) - SASS - Javascript (ES6+) - React(React router, Hooks,Context API, React Transition Group) - Next. . create vs create2, audio streamer, bos21 bokeh, chuck connors son dies, brittni de la mora nude, louisville craiglist, best cam for 305 chevy, huge pig fucks girl video, big boobs milf, bokefjepang, armani black creampie, mecojo a mi hermana co8rr