native-sizeof
A native package to quickly calculate an object size, written in Rust.
Installation
npm install --save native-sizeof
Usage
const { sizeof } = require('native-sizeof');
const object = {
'key': 'value'
}
sizeof(object);
sizeof("hello");
sizeof(123)
sizeof(true)
sizeof(null)
Summary
In javascript, there is no manual memory management, and therefore no sizeof
capabilities, unlike C and other system languages.
However, sometimes it is useful to know how much size your object takes, so it will provide an approximation of how much memory is confused by your app, and how much memory is actually needed by your VM / Container.
Since iterating over an object and summing up the occupied memory is a synchronous task, which blocks the main thread, this library is written in Rust for better performance.
Object size calculation
According to the ECMAScript® Language Specification:
- Each
boolean
value is represented using 2 bytes. - Each
number
value is represented using 8 bytes. - Each
string
value is represented using 2 bytes per character. (so a string of length 3 takes 2 * 3 = 6 bytes).
NOTE: Some JS engines might optimize those numbers, but those are a good upper bound.
Development
Prerequisites
- Node (at least 12)
- Rust (stable)
Building
This will install the relevant development packages from npm and will build the binary from the rust code.
Testing
This runs both Rust tests and JS integration tests.