How to read a file inside a ZIP archive as ArrayBuffer using JSZip

Want to read as a string instead? Read How to read a file inside a ZIP archive as string using JSZip

In JSZip, you can read a compressed file as ArrayBuffer using

zip.file("filename.txt").async("ArrayBuffer").then(function(data) {
    // data is an ArrayBuffer
    // TODO your code goes here

Full example

This is based on our post on How to uncompress file inside ZIP archive using HTML5 & JSZip which reads a local file using a HTML5 file input:

    <input type="file" id="myfile" onchange="onMyfileChange(this)" />

    <script src="" type="text/javascript"></script>
    <script type="text/javascript">
        function onMyfileChange(fileInput) {
            if(fileInput.files[0] == undefined) {
                return ;

            var filename = fileInput.files[0].name;
            var reader = new FileReader();
            reader.onload = function(ev) {
                JSZip.loadAsync( {
                    zip.file("word/document.xml").async("ArrayBuffer").then(function(data) {
                        // data is an ArrayBuffer
                        // TODO Your code goes here!
                }).catch(function(err) {
                    console.error("Failed to open", filename, " as ZIP file:", err);
            reader.onerror = function(err) {
                console.error("Failed to read file", err);