blob64

blob64

A tiny javascript library to turn byte arrays into efficient base64 strings.

Basically, this does what you wish btoa would do with an array of bytes, but doesn't. It's not complicated stuff, but there are some gotchas that this library takes care of for you. In tandem with msgpack, it's a great way to stuff a bunch of data into a url if you have to.

blob64.pack( msgpack.pack( ... ) ) beats btoa( JSON.stringify( ... ) by ~30-65%, depending on your data. (see below)

Compatable with nodejs, script tag includes, and requirejs.

blob64.js (1.0kB)

blob64.min.js (0.5kB)

npm install blob64

var buff = [150,205,135,2,206,0,52,217,33,206,0,52,212,203,206,0,83,93,251,206,2,45,175,212,206,1,101,218,187]

blob64.pack( buff )
// 40 chars (30.3% the size of native btoa)
// "ls2HAs4ANNkhzgA01MvOAFNd+84CLa/UzgFl2rs="

btoa( buff )
// note that this converts buff into a string "150,205,135" and then base64 encodes it
// 132 chars
// "MTUwLDIwNSwxMzUsMiwyMDYsMCw1MiwyMTcsMzMsMjA2LDAsNTIsMjEy
//  LDIwMywyMDYsMCw4Myw5MywyNTEsMjA2LDIsNDUsMTc1LDIxMiwyMDYs
//  MSwxMDEsMjE4LDE4Nw=="

btoa( JSON.stringify( buff ) )
// also 132 chars
// "WzE1MCwyMDUsMTM1LDIsMjA2LDAsNTIsMjE3LDMzLDIwNiwwLDUyLDIx
//  MiwyMDMsMjA2LDAsODMsOTMsMjUxLDIwNiwyLDQ1LDE3NSwyMTIsMjA2
//  LDEsMTAxLDIxOCwxODdd"

blob64.pack([0,0,0])
// "AAAA"
blob64.pack([255,255,255])
// "////"
blob64.pack([1,3,3,7])
// "AQMDBw==" 

Compared to using atob / btoa.

btoa([0,0,0])
// "MCwwLDA="
btoa([255,255,255])
// "MjU1LDI1NSwyNTU="
btoa([1,3,3,7])
// "MSwzLDMsNw=="

Usage with msgpack

var obj = {this:{is:{a:{msgpack:{object:'foo'}}}}};
var packed = blob64.pack( msgpack.pack( obj ) );
// "gaR0aGlzgaJpc4GhYYGnbXNncGFja4Gmb2JqZWN0o2Zvbw=="
msgpack.unpack( blob64.unpack( packed ) )
// {this:{is:{a:{msgpack:{object:'foo'}}}}}

// vs alternatives

btoa( JSON.stringify( obj ) )
// "eyJ0aGlzIjp7ImlzIjp7ImEiOnsibXNncGFjayI6eyJvYmplY3QiOiJmb28ifX19fX0="

btoa( msgpack.pack( obj ) )
// "MTI5LDE2NCwxMTYsMTA0LDEwNSwxMTUsMTI5LDE2MiwxMDUsMTE1LDEyOSwxNjEsOTcsMTI5LDE2NywxMDksMTE1LDEwMywxMTIsOTcsOTksMTA3LDEyOSwxNjYsMTExLDk4LDEwNiwxMDEsOTksMTE2LDE2MywxMDIsMTExLDExMQ=="

In the above examples, blob64 is 68% the size of JSON + btoa, the next closest competitor. This advantage increases quite a bit if your data has lots of integers in it.

Note: This is only especially useful in the browser, as it's functionality is the same as new Buffer([...]).toString('base64') on the server. But in the browser, it beats window.btoa by a nice margin.

MIT Licence

Contributions welcome