for (var i = 0; i < x.files.length; i++) {. To upload a file in React Js, we can use FormData () api of javascript. Let’s say you want to download Codesource.io’s logo. How do I include a JavaScript file in another JavaScript file? src = event. JSON stands for Javascript Object Notation. Let us look at the exmaples of reading and writing files using the fs module on node.js, Let us create a js file named main.js having the following code −. Source. JavaScript memory game Mode (0 for reading and 3 for writing). A file list can be accessed when you select a file using an HTML file input. Example: