node package manager


Sizeof of a JavaScript object in Bytes

JavaScript does not provide sizeof (like in C), and programmer does not need to care about memory allocation/deallocation.

However, according to ECMAScript Language Specification, each String value is represented by 16-bit unsigned integer, Number uses the double-precision 64-bit format IEEE 754 values including the special "Not-a-Number" (NaN) values, positive infinity, and negative infinity.

Having this knowledge, the module calculates how much memory object will allocate.

Please note, that V8 which compiles the JavaScript into native machine code, is not taken into account, as the compiled code is additionally heavily optimized.

npm install object-sizeof

  var sizeof = require('object-sizeof');
  // 2B per character, 6 chars total => 12B 
  console.log(sizeof({abc: 'def'}));
  // 8B for Number => 8B 
  var param = { 
    'a': 1, 
    'b': 2, 
    'c': {
      'd': 4
  // 4 one two-bytes char strings and 3 eighth-bytes numbers => 32B 

The MIT License (MIT)

Copyright (c) 2015, Andrei Karpushonak aka @miktam