How to achieve "Base64 encoded SHA-1 hash of a string" in Node.js

Have you tried using crypto? http://nodejs.org/api/crypto.html

var ciphers = crypto.getCiphers();
console.log(ciphers); // ['AES-128-CBC', 'AES-128-CBC-HMAC-SHA1', ...]

var hashes = crypto.getHashes();
console.log(hashes); // ['sha', 'sha1', 'sha1WithRSAEncryption', ...]

From website:

crypto.createHash(algorithm)# Creates and returns a hash object, a cryptographic hash with the given algorithm which can be used to generate hash digests.

algorithm is dependent on the available algorithms supported by the version of OpenSSL on the platform. Examples are 'sha1', 'md5', 'sha256', 'sha512', etc. On recent releases, openssl list-message-digest-algorithms will display the available digest algorithms.

Example: this program that takes the sha1 sum of a file

var filename = process.argv[2];

var crypto = require('crypto');
var fs = require('fs');

var shasum = crypto.createHash('sha1');

var s = fs.ReadStream(filename);
s.on('data', function(d) {
  shasum.update(d);
});

s.on('end', function() {
  var d = shasum.digest('hex');
  console.log(d + '  ' + filename);
});