JSZip
Create, read and edit .zip files with Javascript
How?
Why?
- JavaScript today is capable of generating a lot of data. The easiest way to deliver multiple files to your users is in a zip file. Instead of wasting server resources and bandwidth you can get the client to do it for you.
- Because it's cool!
Tell me more!
Browser support
| Yes | Yes | Yes | Yes | Yes |
| Tested with the latest version | Tested with 3.0 / 3.6 / latest version | Tested with the latest version | Tested with the latest version | Tested with IE 6 / 7 / 8 / 9 / 10 |
While JSZip should work everywhere, the tricky part is to give the zip file to the user.
Browser support for data URI scheme with zip
| 7.5+ | 3.0+ | Yes | Yes | No |
| Filename is "default.zip" | Filename is random alphanumeric with ".part" extension | Filename is "Unknown" (no extension) | Filename is "download.zip" on OSX and Linux, and just "download" on Windows (issue #9) | Only supports data URLs for some content. (May be able to use MHTML?) |
Filename problems
The biggest issue with JSZip is that the filenames are very awkward, Firefox generates filenames such as a5sZQRsx.zip.part (see bugs 367231 and 532230), and Safari isn't much better with just Unknown. Sadly there is no pure Javascript solution (and working in every browsers) to this. However...
Solution-ish: Downloadify
Downloadify uses a small Flash SWF to download files to a user's computer with a filename that you can choose. Doug Neiner has added the dataType option to allow you to pass a zip for downloading. Follow the Downloadify demo with the following changes:
zip = new JSZip();
zip.add("Hello.", "hello.txt");
Downloadify.create('downloadify',{
...
data: function(){
return zip.generate();
},
...
dataType: 'base64'
});
Other solution-ish: Blob URL
With some recent browsers come a new way to download Blobs (a zip file for example) : blob urls. The download attribute on <a> allows you to give the name of the file. Blob urls start to be widely supported but this attribute is currently only supported in Chrome and Firefox (>= 20). See the example.
var blob = zip.generate({type:"blob"});
myLink.href = window.URL.createObjectURL(blob);
myLink.download = "myFile.zip";
Usage with Google Gears
Franz Buchinger has written a brilliant tutorial on using JSZip with Google Gears (part 2). If you want to let your Gears users download several files at once I really recommend having a look at some of his examples.
Reading a zip file from an ajax call
When doing an ajax call to get the binary data, the browser will try to interpret the binary as text, corrupting it. The solution is to set the mimetype to 'text/plain; charset=x-user-defined'. This solution works well in all browsers but IE. If you need IE support, please see what is done in the file test/index.html.
An other solution is to use a modern browser (supporting xhr2) : setting xhr.type = 'arraybuffer'; will do the trick, JSZip supports ArrayBuffers. Please see the example.
Reading a local zip file (File API)
JSZip supports (if available in the browser) the File API : reading a local zip file is simple : new JSZip(readerEvent.target.result);. Please see the complete example for more details.
Documentation
new JSZip()
new JSZip(data [,options])
load() for more details and
this for the limitations.
data (same types as
load()) the content of the zip file to load.
options (Object) options to pass to the
load() method..
new JSZip(zipDataFromXHR, {base64:false});
// same as
var zip = new JSZip();
zip.load(zipDataFromXHR, {base64:false});
file(name)
name (String) the name of the file.
null otherwise. The file has the following structure :
-
namethe absolute path of the file -
datathe data contained in the file -
optionsthe options of the file. The available options are :-
base64, boolean, cf file(name, data [,options]) -
binary, boolean, cf file(name, data [,options]) -
dir, boolean, true if this is a directory -
date, date, cf file(name, data [,options])
-
-
asText(), string, the content as an utf8 string (utf8 encoded if necessary). -
asBinary(), string, the content as binary (utf8 decoded if necessary). -
asArrayBuffer(), ArrayBuffer, need a compatible browser. -
asUint8Array(), Uint8Array, need a compatible browser.
var zip = new JSZip();
zip.file("file.txt", "content");
zip.file("file.txt").name // "file.txt"
zip.file("file.txt").data // "content"
zip.file("file.txt").options.dir // false
// utf8 example
var zip = new JSZip(zipFromAjaxWithUTF8);
zip.file("amount.txt").data // "€15"
zip.file("amount.txt").asText() // "€15"
zip.file("amount.txt").asArrayBuffer() // an ArrayBuffer containing €15
zip.file("amount.txt").asUint8Array() // an Uint8Array containing €15
file(regex)
regex (RegExp) the regex to use.
var zip = new JSZip();
zip.file("file1.txt", "content");
zip.file("file2.txt", "content");
zip.file(/file/); // array of size 2
// example with a relative path :
var folder = zip.folder("sub");
folder
.file("file3.txt", "content") // relative path from folder : file3.txt
.file("file4.txt", "content"); // relative path from folder : file4.txt
folder.file(/file/); // array of size 2
folder.file(/^file/); // array of size 2, the relative paths start with file
// arrays contain objects in the form:
// {name: "file2.txt", data: "content", dir: false}
file(name, data [,options])
name (String) the name of the file.
data (String/ArrayBuffer/Uint8Array) the content of the file.
options (Object) the options :
-
base64(boolean) set totrueif the data is base64 encoded. For example image data from a<canvas>element. Plain text and HTML do not need this option. -
binary(boolean) defaults totrueif the data is base64 encoded,falseotherwise. If set to false then UTF-8 characters will be encoded. If the data is an ArrayBuffer or an Uint8Array, this will be set to true. -
date(Date) use it to specify the last modification date. If not set the current date is used. -
optimizedBinaryString(boolean), default false. Set it to true if (and only if) the input has already been prepared with a 0xFF mask.
zip.add("Hello.txt", "Hello World\n");
zip.add("smile.gif", "R0lGODdhBQAFAIACAAAAAP/eACwAAAAABQAFAAACCIwPkWerClIBADs=", {base64: true});
zip.add("magic.txt", "U2VjcmV0IGNvZGU=", {base64: true, binary: false});
zip.add("Xmas.txt", "Ho ho ho !", {date : new Date("December 25, 2007 00:00:01")});
zip.add("folder/file.txt", "file in folder");
zip.add("animals.txt", "dog,platypus\n").add("people.txt", "james,sebastian\n");
// result : Hello.txt, smile.gif, magic.txt, Xmas.txt, animals.txt, people.txt,
// folder/, folder/file.txt
folder(name)
name (String) the name of the directory.
zip.folder("images");
zip.folder("css").add("style.css", "body {background: #FF0000}");
// or specify an absolute path (using forward slashes)
zip.add("css/font.css", "body {font-family: sans-serif}")
// result : images/, css/, css/style.css, css/font.css
folder(regex)
regex (RegExp) the regex to use.
var zip = new JSZip();
zip.folder("home/Pierre/videos");
zip.folder("home/Pierre/photos");
zip.folder("home/Jean/videos");
zip.folder("home/Jean/photos");
zip.folder(/videos/); // array of size 2
zip.folder("home/Jean").folder(/^vid/); // array of 1
remove(name)
Delete a file or folder.
name (String) the name of the file/folder to delete.
var zip = new JSZip();
zip.add("Hello.txt", "Hello World\n");
zip.add("temp.txt", "nothing").remove("temp.txt");
// result : Hello.txt
zip.folder("css").add("style.css", "body {background: #FF0000}");
zip.remove("Hello.txt").remove("css");
//result : empty zip
generate(options)
options (Object) the options to generate the zip file :
-
base64(boolean) deprecated, use "type" instead.falseto get the result as a raw byte string. Default :true, encode as base64. -
compression(String) the compression method to use."STORE"(no compression) by default, you can use"DEFLATE"(include the file jszip-deflate.js) or write your own. -
type(String) the type of zip to return. The possible values are :-
base64(default) : the result will be a string, the binary in a base64 form. -
string: the result will be a string in "binary" form, 1 byte per char. -
uint8array: the result will be a Uint8Array containing the zip. This requires a compatible browser. -
arraybuffer: the result will be a ArrayBuffer containing the zip. This requires a compatible browser. -
blob: the result will be a Blob containing the zip. This requires a compatible browser.
-
JSZip.support). This method will throw an exception otherwise.
content = zip.generate(); location.href="data:application/zip;base64,"+content;
content = zip.generate({type:"string"});
for (var c = 0; c < content.length; c++) {
console.log(content.charCodeAt(c));
// do other things
}
load(data, options)
data (String/ArrayBuffer/Uint8Array) the zip file
options (Object) the options to load the zip file :
-
base64(boolean)trueif the data is base64 encoded,falsefor binary. Default :false. -
checkCRC32(boolean)trueif the read data should be checked against its CRC32. Default :false.
var zip = new JSZip(); zip.load(zipDataFromXHR);
Zip features supported by this method
- Compression (
DEFLATEwith jszip-deflate.js) - zip with data descriptor
- ZIP64
- UTF8 in file name, UTF8 in file content
Zip features not (yet) supported
- password protected zip
- multi-volume zip
filter(predicate)
predicate (function) the predicate to use :
function (relativePath, file) {...} It takes 2 arguments : the relative path and the file.
-
relativePath(String) The filename and its path, reliatively to the current folder. -
file(Object) The file being tested. Like the result offile(name), the file has the form{name:"...", data:"...", options:{...}}. - Return true if the file should be included, false otherwise.
var zip = new JSZip().folder("dir");
zip.file("readme.txt", "content");
zip.filter(function (relativePath, file){
// relativePath == "readme.txt"
// file = {name:"dir/readme.txt",data:"content",options:{...}}
return true/false;
});
JSZip.support
If the browser supports them, JSZip can take advantage of some new features : ArrayBuffer, Blob, Uint8Array. To know if JSZip can use them, you can check the JSZip.support object. It contains the following properties :
-
arraybuffer: true if JSZip can read and generate ArrayBuffer, false otherwise. -
uint8array: true if JSZip can read and generate Uint8Array, false otherwise. -
blob: true if JSZip can read and generate Blob, false otherwise.
Loading zip files, limitations
All the features of zip files are not supported. Classic zip files will work but encrypted zip, multi-volume, etc are not supported and the load() method will throw an Error.
ZIP64 files can be loaded, but only if the zip file is not "too big". ZIP64 uses 64bits integers but Javascript represents all numbers as 64-bit double precision IEEE 754 floating point numbers (see section 8.5). So, we have 53bits for integers and bitwise operations treat everything as 32bits. So if all the 64bits integers can fit into 32 bits integers, everything will be fine. If it's not the case, you will have other problems anyway (see next limitation).
An other limitation comes from the browser (and the machine running the browser). A compressed zip file of 10M is common and easily opened by desktop application, but not in a browser. The processing of such a beast is likely to be painful : the browser will eat hundreds of megabytes while using CPU like never.
If you use an old browser, things will be worse. For example, IE6 and IE7 are quite slow to to execute the unit tests, and they completely freeze as soon as they try to handle larger files.
Conclusion : reading small files is OK, reading others is not.
Reading and generating a zip file won't give you back the same file. Some data are discarded (file metadata) and other are added (subfolders).
Changelog
1.0.1 2013-03-04
- Fixed an issue when generating a compressed zip file with empty files or folders, see #33.
- With bad data (
nullorundefined), asText/asBinary/asUint8Array/asArrayBuffer methods now return an empty string, see #36.
1.0.0 2013-02-14
First release after a long period without version.