If you need to save really large files bigger than the blob's size limitation or don't have
enough RAM, then have a look at the more advanced StreamSaver.js
that can save data directly to the hard drive asynchronously with the power of the new streams API. That will have
support for progress, cancelation and knowing when it's done writing
FileSaver.js
FileSaver.js is the solution to saving files on the client-side, and is perfect for
web apps that generates files on the client, However if the file is coming from the
server we recommend you to first try to use Content-Disposition attachment response header as it has more cross-browser compatiblity.
Looking for canvas.toBlob() for saving canvases? Check out
canvas-toBlob.js for a cross-browser implementation.
Supported Browsers
| Browser |
Constructs as |
Filenames |
Max Blob Size |
Dependencies |
| Firefox 20+ |
Blob |
Yes |
800 MiB |
None |
| Firefox < 20 |
data: URI |
No |
n/a |
Blob.js |
| Chrome |
Blob |
Yes |
2GB |
None |
| Chrome for Android |
Blob |
Yes |
RAM/5 |
None |
| Edge |
Blob |
Yes |
? |
None |
| IE 10+ |
Blob |
Yes |
600 MiB |
None |
| Opera 15+ |
Blob |
Yes |
500 MiB |
None |
| Opera < 15 |
data: URI |
No |
n/a |
Blob.js |
| Safari 6.1+* |
Blob |
No |
? |
None |
| Safari < 6 |
data: URI |
No |
n/a |
Blob.js |
| Safari 10.1+ |
Blob |
Yes |
n/a |
None |
Feature detection is possible:
try {
var isFileSaverSupported = !!new Blob;
} catch (e) {}
IE < 10
It is possible to save text files in IE < 10 without Flash-based polyfills.
See ChenWenBrian and koffsyrup's saveTextAs() for more details.
Safari 6.1+
Blobs may be opened instead of saved sometimes—you may have to direct your Safari users to manually
press ⌘+S to save the file after it is opened. Using the application/octet-stream MIME type to force downloads can cause issues in Safari.
iOS
saveAs must be run within a user interaction event such as onTouchDown or onClick; setTimeout will prevent saveAs from triggering. Due to restrictions in iOS saveAs opens in a new window instead of downloading, if you want this fixed please tell Apple how this WebKit bug is affecting you.
Syntax
Import saveAs() from file-saver
import { saveAs } from 'file-saver';
FileSaver saveAs(Blob/File/Url, optional DOMString filename, optional Object { autoBom })
Pass { autoBom: true } if you want FileSaver.js to automatically provide Unicode text encoding hints (see: byte order mark). Note that this is only done if your blob type has charset=utf-8 set.
Examples
Saving text using require()
var FileSaver = require('file-saver');
var blob = new Blob(["Hello, world!"], {type: "text/plain;charset=utf-8"});
FileSaver.saveAs(blob, "hello world.txt");
Saving text
var blob = new Blob(["Hello, world!"], {type: "text/plain;charset=utf-8"});
FileSaver.saveAs(blob, "hello world.txt");
Saving URLs
FileSaver.saveAs("https://httpbin.org/image", "image.jpg");
Using URLs within the same origin will just use a[download].
Otherwise, it will first check if it supports cors header with a synchronous head request.
If it does, it will download the data and save using blob URLs.
If not, it will try to download it using a[download].
The standard W3C File API Blob interface is not available in all browsers.
Blob.js is a cross-browser Blob implementation that solves this.
Saving a canvas
var canvas = document.getElementById("my-canvas");
canvas.toBlob(function(blob) {
saveAs(blob, "pretty image.png");
});
Note: The standard HTML5 canvas.toBlob() method is not available in all browsers.
canvas-toBlob.js is a cross-browser canvas.toBlob() that polyfills this.
Saving File
You can save a File constructor without specifying a filename. If the
file itself already contains a name, there is a hand full of ways to get a file
instance (from storage, file input, new constructor, clipboard event).
If you still want to change the name, then you can change it in the 2nd argument.
// Note: Ie and Edge don't support the new File constructor,
// so it's better to construct blobs and use saveAs(blob, filename)
var file = new File(["Hello, world!"], "hello world.txt", {type: "text/plain;charset=utf-8"});
FileSaver.saveAs(file);
Installation
# Basic Node.JS installation
npm install file-saver --save
bower install file-saver
Additionally, TypeScript definitions can be installed via:
# Additional typescript definitions
npm install @types/file-saver --save-dev
FileSaver.js 是一个客户端 JavaScript 库，实现了 saveAs() 接口，让网页应用能够为直接在浏览器中生成的数据触发文件下载。