Leanpub: recover lost manuscript from browser cache

leanpub-recovery.js

// Leanpub: recovering lost manuscript
// -----------------------------------
//
// I lost the whole content of my Leanpub book after switching to GitHub.
// Fortunately, the manuscript files were still on my browser local storage.
// I was able to recover the complete manuscript using the following script.
//
// If this happens to you too, follow these steps:
//
// 1. Open your browser to https://leanpub.com
// 2. Open a developer console
// 3. Copy this script
// 4. Paste it in the developer console
// 5. Press enter to trigger the execution of the script
// 6. The browser will complain that a lot of files are being download,
//    just click on "Allow".
//
// Admittedly, 6 steps sounds like a lot, but it takes no more than 15 seconds. 

function download(data, filename, type) {
    var file = new Blob([data], {type: type});
    var a = document.createElement("a");
    var url = URL.createObjectURL(file);
    a.href = url;
    a.download = filename;
    document.body.appendChild(a);
    a.click();
    setTimeout(function() {
        document.body.removeChild(a);
        window.URL.revokeObjectURL(url);  
    }, 0); 
}

for( var key in localStorage ) {
    var obj = JSON.parse(localStorage[key]);
    if( obj && obj.filename && obj.content ) {
	    download(obj.content, obj.filename, 'text/markdown');
	}
}

See the script in action: https://youtu.be/4VysLo1zvh4

Whoops! I just discover that Leanpub stores a history in the "Versions" tab 😀
A version is saved just before the switch to GitHub, so it's easy to recover from that.

I'm keeping this script online as it may serve as an alternative solution.