chrahunt/filesaver.js

FileSaver.js lets a website save files directly to a visitor's computer. Instead of sending data to a server and then making the user download it from there, your web app can create the file right in the browser and hand it off as a download. This is handy for apps that generate files on the fly or handle sensitive information that should never leave the user's machine. Under the hood, it provides a simple saveAs command. You give it some data, like text or an image, and a filename, and it packages that into a downloadable file. The library smooths over the differences between browsers so your download button works consistently whether your visitor is on Chrome, Firefox, Edge, or Safari, including older versions that don't natively support this kind of file saving. A founder building a photo editor might use it to let users export their edited image as a PNG. A PM working on a reporting dashboard could let users download a generated text or CSV file. A developer building an offline note-taking app could save a backup file locally. Anyone building a web app that needs a "download" button for data generated in the browser can benefit. One tradeoff worth noting: there are limits on how large a file can be. Depending on the browser, the cap ranges from around 500 to 800 megabytes, and if the user's device doesn't have enough memory, the download can fail. For very large files, the README points to a different approach that streams data straight to disk. There are also some quirks on iOS and older Safari where files may open in a new window instead of downloading immediately, requiring the user to save manually.