如何计算压缩对象的大小？

Question

如何计算对象或javascript中压缩对象的实际大小（字节），而不是基于对象中字符的长度？

我尝试了object-sizeof npm库，但是它会根据字符长度返回大小。在下面的代码中，jsonCompressCheck是一个大的Json Object，我需要压缩它并且我想获取大小以便知道它的效率是

console.log("Actual Object Size: "+sizeof($scope.jsonCompressCheck));
var zlib = require('zlib');
var sizeof = require('object-sizeof');
  zlib.deflate(JSON.stringify($scope.jsonCompressCheck),function(err, buffer) {
            if (!err) {
              console.log("USing Deflate Size of: ");
              console.log("Byte Length: "+Buffer.byteLength(buffer));
              console.log(sizeof(buffer));
             $scope.compressed = buffer;
            }
          });
     zlib.gzip(JSON.stringify($scope.jsonCompressCheck),function(err, buffer) {
            if (!err) {
              console.log("USing gzip: ");
              console.log("Byte Length: "+Buffer.byteLength(buffer));
              console.log(sizeof(buffer));
             $scope.compressed = buffer;
            }
          });