Open and edit the uploaded files in React Uploader component (2024)

FAQs

How do I open an upload file in React? ›

In React file upload is implemented by using the HTML input element and some JavaScript to make a POST/PUT request to the server with the FormData that contains the selected files. Your server will then need to process multipart form data to accept file uploads.

In the browser environment, clients can initiate image upload by browsing files using an input element or the drag and drop API. You can then use the URL API or the FileReader API to read the image files and preview them.

Typically, the file upload component will be used in a form and when working with forms in React, the component stores the form data in the state. Thus, for the parent component to also store the uploaded files, we need the file upload component to send it.

You can retrieve the saved file path in the uploader success event and assign it to custom attribute (data-file-name) value of the respective file list element to open the uploaded file. Click the respective file element to create a new request along with saved file path using http header.

First, let's create a Form in React so that the user can upload a CSV file. We created a simple form and our input items. With the accept feature of the input element, we specify that the format of the file can only be CSV. Now, let's load and read the CSV file selected by the user with FileReader.

Creating FilePreviewer Component

import { useState, useRef } from "react"; Create a FilePreviewer function and export it as default. Now we render the UI for FIle Picker and in that there will be two buttons. One for selecting files and the other for clearing file input.

Transmitting a file from your computer to another computer. "File upload" is essentially the same term as "upload," because most of the time data are transmitted as a structural unit known as a "file."

What is Memoization in React component? ›

Memoization is an optimization technique for accelerating computer programs by caching the results of heavy function calls and returning them when similar inputs are encountered repeatedly. Simply, React memoization is similar to caching.

The first way to import images in React is by adding them to the source folder (testapp/src/) of your application. Thanks to webpack, it is possible to import a file right in a JavaScript module. By default, when you create a react app with create-react-app, React adds logo.svg in the src folder.

When a file is successfully uploaded to the server, it is placed on a temporary folder. The path to this directory can be found in the "files" object, passed as the third argument in the parse() method's callback function.

npm install '@react-pdf-viewer/default-layout'; Now, we will see how to apply the logic to preview the pdf in react js application. Now run the application with the npm start command and you can see the file field render on the page. Next click on the choose file option, then select a pdf file and click on upload.

JavaScript Code

The fileValidation() function contains the complete file type validation code. This JavaScript function needs to call for file extension validation. Image file extensions regex is defined in allowedExtensions variable. If you want to validate other file types, change the regex with allowed extensions.

A HandleParse function will parse CSV data, use the papa parser, and set the data state to the columns of CSV files. Hence, it will return the component that consists of an input element to take an uploaded file, a button to parse data on click, and the container to view errors or the parsed data.

You have to call the document. getElementById() method in the useEffect hook or when an event occurs. A commonly used convention in React is to only use the document. getElementById method when you don't have access to the DOM element and can't set a ref on it.

How do I open a DOCX file in React? ›

We access a DOM element using the current property of a reference created with the React. createRef() function. React will update this property with an actual DOM element after render and before update events. That means that we can access the DOM element in componentDidMount and componentDidUpdate functions.

Run the React Application

A new browser window will pop up with your newly created React App! If not, open your browser and type localhost:3000 in the address bar.

How do I upload a file and view in React JS? ›

The first approach to file uploading in React. js is to use JavaScript. This involves creating a form with an input field of type "file" and then using JavaScript to handle the file upload process.