React functional component loop through array. 2, there is a new syntax <> to create fragments.
React functional component loop through array This means that you shouldn’t reassign items inside an array like arr[0] = 'bird', and you also shouldn’t use methods that mutate the array, such as push() and pop(). In particular, we will deep dive into one of the utility methods, `React. With the ShowcaseApplicants instantiation, the component accesses the array using the applicants props. Read this article for more information. Jul 23, 2025 · Rendering dynamic data in ReactJS is one of the most fundamental tasks when building interactive web applications. Like with objects, you should treat arrays in React state as read-only. map function to render a list of components. I want to convert that using Objects. If you're having a specific component rendering a post or note, it would be better to do it via props. Apr 10, 2023 · Next, we want to pass the data in the array to a new component that showcases further data about each applicant. Apr 5, 2014 · Using the Array map function is a very common way to loop through an Array of elements and create components according to them in React. In React, markup is a part of your code, so you can use tools like variables and functions to tidy up complex expressions. map() when being used. React will not throw away the cached function unless there is a specific reason to do that. map () method. I call the therapists in an array from an database and I need to map them to render in a card, inside an functional component. due to sorting), get inserted, or get deleted. I'm not sure exactly how you're planning on getting your data to your component but this example is how you could do it via the state. For loop Consider we have an array of users… Apr 6, 2024 · # Loop through an Array of Objects in React To loop through an array of objects in React: Use the map() method to iterate over the array. Sep 27, 2024 · Dynamic Rendering: It simplifies how we iterate over data and render UI components. After that was done, we used array. Aug 7, 2025 · In React, when we are working with dynamic data, it is common to render a list of items. It iterates over the list of items in the array and returns a list of React components map () function is called over the Jan 12, 2022 · I am trying to create a table component where the component will serve some special className to its specific children. When working on a complex or huge enterprise-level application, you probably want to write better code that can be unit tested, type-checked, and debugged easily. This makes it easy for any developer to comfortably handle common programming techniques in React, such as looping through a set of items, creating and invoking functions, storing data in local variables, and so on. This style works well for simple conditions, but use it in moderation. Our functional React component returns a single div element with some JSX inside. Learn how to loop through an array in React and render it on the page, including a key for each element, using the . key () method, but when I iterate through it, values won't be printed on view page. Understanding how to iterate over arrays and create components dynamically is crucial in building interactive and dynamic React applications. For example, in development, React throws away the cache when you edit the file of your component. Functional Component with Props In React, a functional component with props is a JavaScript function that receives an object called props as its argument. Learn how to use Array. map () Array. One of the most common scenarios is rendering an array of objects, such as a list of users, products, or posts, in the user interface (UI). Jul 23, 2025 · Step 5: Map the Data into React Component Import the users list and info component and map the data using array map, passing the required props to Info component. Feb 11, 2019 · How can I implement this for an array of elements? Obviously not like that: (I knew it even I did not try it:) Jul 16, 2020 · React allows you to easily write JavaScript code inside your components. Functional Approach: React encourages the use of pure functions and immutable data structures. However, the principles still remain with regard to looping through React components. Basic List Component Usually you would render lists inside a component. Please check it out if you're interested in this topic! Try it on CodePen This code displays a bullet list of numbers between 1 and 5. map () method in React to iterate through an array and render a list of elements. toArray`, that React gives us, which helps to iterate over the children in a way which ensures performance and determinism. map() to map the applicants' name, number of websites built, and location which was rendered Aug 22, 2015 · With React >= 16, it is possible to return multiple elements from the same component without needing an extra html element wrapper. map() function. Children. Aug 24, 2017 · Learn how to loop through a simple array of objects in React using efficient and tidy methods. Aug 5, 2025 · The loop iterates through the colors array, generating div elements with inline styling for each color. Oct 5, 2020 · If we are working on any React project we have to play with arrays and objects for data. In our case, we loop Oct 21, 2022 · Using the map() Method You can use the map() method on an array to loop through the elements and create components, or generate JSX, inside the return block. Example 1: This example uses array map method to iterate the users and passes data as props to render the list of users. The function you pass to map() gets called for each element in the array. In React, loops are not used in the traditional sense as in standard JavaScript. This guide demonstrates how to implement loops in common use cases, such as rendering a list of static data Aug 18, 2020 · React does not come with a type-check system out of the box. g. 2, there is a new syntax <> to create fragments. Fragments don’t get traversed. Apr 7, 2024 · We can render the results array directly in our JSX code because it's an array of JSX elements I've also written a detailed guide on how to loop through an object in React. Ways to render a list 1. prototype. Manipulating the DOM with Refs React automatically updates the DOM to match your render output, so your components won’t often need to manipulate it. This becomes important if your array items can move (e. Using Array. const BasicTable = ({ children }) => { const RenderChild = Chi You can’t call it inside loops or conditions. Arrays don’t count as individual nodes, but their children do. Nov 10, 2020 · When you have multiple items that you want to render inside your React component, you can use a for statement inside your function component to loop over the array. However, sometimes you might need access to the DOM elements managed by React—for example, to focus a node, scroll to it, or measure its size and position. Learn how to loop through an array of items with React and use the . Dec 13, 2023 · While it is technically possible to use a for loop in the render method of a React component, there are alternative approaches that are more in line with React's declarative and functional programming principles. js. This method is frequently used to dynamically render lists of items. The map() method returns a new array of React elements which can then be rendered within your component. Most of these ways are covered in this article about React JSX loops, and although it's using React examples, everything from it can be used in React Native. Again, because we’re using JSX, we can have our JavaScript Map function output HTML. It’s like magic. In React, there are several methods to render the list efficiently. This is a great way to do a pretty efficient and tidy loop in JSX. The method returns a new array with the results of the passed-in function. So we have our shop items and now we want to create a child component which we call Item. map () One of the most common ways (probably the most common way) of rendering an array of components in React is by making use of the Array. map function will iterate (loop) over an existing array and return a new array based on a callback function that Caveats Empty nodes (null, undefined, and Booleans), strings, numbers, and React elements count as individual nodes. Nov 7, 2023 · Final Thoughts To wrap up, using map(), forEach(), and reduce() correctly makes a big difference in React apps with TypeScript. Arrays are used to store multiple data into a single variable and objects are a collection of properties To iterate through an array of data and create numerous instances of a component in React, we can use the map function in JavaScript. # Use the Array. Jul 14, 2021 · Rendering an array of components with Array. Aug 21, 2025 · Re-rendering: If the component's props or state change, React updates the virtual DOM tree accordingly and triggers the component to re-render. TypeScript is a compiled superset of JavaScript that can do just that. Logical AND operator (&&) Nov 27, 2018 · So if you wanted to loop through an array of child components, but preferred the first method we showed you, then you can! At the end of the day, it’s all regular Javascript! So there you have it, we have shown you three powerful ways to loop through arrays using the latest Javascript techniques in React. In this guide, you will get a quick overview of how to use TypeScript with React and learn to enforce Apr 12, 2022 · How can I create and loop through a custom array within a react functional component? Asked 3 years, 5 months ago Modified 3 years, 5 months ago Viewed 134 times Learn how to use the . Users can add new colors to the list using the approach2Fn function, demonstrating dynamic rendering and user interaction within a React component. We can refactor the previous example into a component that accepts an array of numbers and outputs a list of elements. map () is a built-in JavaScript function provided by JavaScript. Learn how to import local images to a React component as an array of objects and loop through them using the map() function. Since 16. Therefore, class components were used instead of functional components. map function which looks like []. Remember, map() is for creating new arrays, forEach() is for doing Mar 12, 2021 · I'm trying to get a list of array items from an api response using useEffect, as a result I'm getting a list of objects. Keys tell React which array item each component corresponds to, so that it can match them up later. Why? Because It allows us to write JavaScript inside HTML. How to Loop Through Arrays in React React leverages JavaScript’s map() function to iterate over arrays and create components or elements for each item in the array. map() method to render an array's elements To iterate over an array and render its elements directly in your JSX code, use the Array. . Aug 4, 2021 · In this article, we’ll discuss and learn about the use case of iterating over React `children` and the ways to do it. To render an array of objects in React we will iterate the objects using an array map and use the following approaches to render data on the Dec 14, 2022 · In this tutorial, we are going to learn about how to loop through array of elements in a react. I would read the List and Keys docs for React. The Array. Feb 14, 2020 · I want to map the therapists array from the functional component above. If your components get messy with too much nested conditional markup, consider extracting child components to clean things up. The traversal does not go deeper than React elements: they don’t get rendered, and their children aren’t traversed. Next, we simply loop through the names array using the brilliantly simple Map Array function. map() in React to render UI of arrays by wrapping them in curly braces for JavaScript interpretation. Oct 24, 2019 · How to use React + TypeScript to render components by looping through an array? Asked 5 years, 10 months ago Modified 5 years, 10 months ago Viewed 16k times Mar 1, 2017 · There are many other ways to loop through list of elements in react native, and which way you'll use depends on what do you need to do. JSX is absolutely brilliant. Oct 27, 2018 · Note: This post was written before the creation of React Hooks. Jan 10, 2024 · Looping through arrays in React is a fundamental concept that allows developers to render lists of elements efficiently. If you need that, extract a new component and move the state into it. Updating arrays without mutation In JavaScript, arrays are just another kind of object. ndag0wi1uczpxoxl0qj4t6dugpoqzm4nmcld55pof