Hash transform that creates a hash (checksum) from an input stream leaving stream unchanged and is then able to be piped to input of another stream.
hash-transform is written in ecma6 so I would recommend running nodejs v4.0 or greater (no harmony flag needed)
$ npm install hash-transform
##test
$ npm test
###constructor
new HashTransform(algorithm[, encoding]);
###hashing file stream
var HashTransform = require('hash-transform');
var path = require('path');
var fs = require('fs');
var file = path.resolve('./test/data/test.txt');
var alg = 'sha256';
var hash = new HashTransform(alg);
var fi = fs.createReadStream(file);
fi.pipe(hash).pipe(process.stdout);
hash.on('end', function(){
console.log(hash.hash);
});
MIT