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Read W3C Blob & File objects as a Node stream. Very useful with "browserify" and "primus" with "ejson" using pipe().


If you are already generating a bundle using browserify (or something similar), you can use it directly:

npm install readable-blob-stream --save
var ReadableBlobStream = require('readable-blob-stream');

Or, you can generate a standalone javascript file by cloning or downloading this repo and typing:

npm install
npm run bundle

Look in the build directory to find the generated file. This is a UMD module. Which means you can either require() it using browserify, load it using AMD, or access it as the global window.ReadableBlobStream


<!DOCTYPE html>
<script src="readable-blob-stream.js"></script>
window.addEventListener('DOMContentLoaded', function()
    var myfile = document.getElementById('myfile');
    myfile.addEventListener('change', function()
        var file = myfile.files[0];
        if (!file) { return; }
        var stream = new ReadableBlobStream(file);
        // or: 
        //var stream = new ReadableBlobStream(file, {highWaterMark : 128, encoding: 'utf8'}); 
        stream.on('error', function(err)
            console.log('error while reading your file:', err);
        stream.on('end', function()
            console.log('there will be no more data.');
        stream.on('data', function(data)
            // if you do not set an encoding, 
            // "data" is both a Buffer and an Uint8Array 
            console.log('got %d amount of data: ', data.length, data);
        // If you are using primus you can simply use: 
        //     stream.pipe(spark); 
        // instead of using the 'data' listener 
<input type="file" id="myfile">