hash: function()

in lib/util.js [447:496]

• 29 lines of code
• 20 McCabe index (conditional complexity)

    hash: function(algorithm, data, digest, callback) {
      var hash = util.crypto.createHash(algorithm);
      if (!digest) { digest = 'binary'; }
      if (digest === 'buffer') { digest = undefined; }
      if (typeof data === 'string') data = util.buffer.toBuffer(data);
      var sliceFn = util.arraySliceFn(data);
      var isBuffer = util.Buffer.isBuffer(data);
      //Identifying objects with an ArrayBuffer as buffers
      if (util.isBrowser() && typeof ArrayBuffer !== 'undefined' && data && data.buffer instanceof ArrayBuffer) isBuffer = true;

      if (callback && typeof data === 'object' &&
          typeof data.on === 'function' && !isBuffer) {
        data.on('data', function(chunk) { hash.update(chunk); });
        data.on('error', function(err) { callback(err); });
        data.on('end', function() { callback(null, hash.digest(digest)); });
      } else if (callback && sliceFn && !isBuffer &&
                 typeof FileReader !== 'undefined') {
        // this might be a File/Blob
        var index = 0, size = 1024 * 512;
        var reader = new FileReader();
        reader.onerror = function() {
          callback(new Error('Failed to read data.'));
        };
        reader.onload = function() {
          var buf = new util.Buffer(new Uint8Array(reader.result));
          hash.update(buf);
          index += buf.length;
          reader._continueReading();
        };
        reader._continueReading = function() {
          if (index >= data.size) {
            callback(null, hash.digest(digest));
            return;
          }

          var back = index + size;
          if (back > data.size) back = data.size;
          reader.readAsArrayBuffer(sliceFn.call(data, index, back));
        };

        reader._continueReading();
      } else {
        if (util.isBrowser() && typeof data === 'object' && !isBuffer) {
          data = new util.Buffer(new Uint8Array(data));
        }
        var out = hash.update(data).digest(digest);
        if (callback) callback(null, out);
        return out;
      }
    },