node-self

🤙 self property in Node.js

Table of contents

• Features
• Compatibility
• How to use?
• How it works?
• License

What is this?

You can use self property in Node.js via this module.

// In Browser (Window context)
console.log(self); // Window { ... }

// In Browser (Dedicate worker context)
console.log(self); // DedicatedWorkerGlobalScope { ... }

// But, in Node.js
console.log(self); // ReferenceError: self is not defined

Why?: self property is not implemented in Node.js.

Features

You can use self property in Node.js.

• Super lightweight
• Pure Javascript
• Zero dependencies

Compatibility

Both Browser and Node.js.

How to use?

Just use self. It's returns appropriate Global Object (Context Dependent)

Import index.js

// CommonJS
require('node-self');

// ES6+
import 'node-self';

or paste this code on the top

void !function () {
  typeof self == 'undefined'
    && typeof global == 'object'
    && (global.self = global);
}();

There are can be self (Global Object)

• Browser
  • Window
  • WorkerGlobalScope
    • DedicatedWorkerGlobalScope
    • SharedWorkerGlobalScope
    • ServiceWorkerGlobalScope
• Node.js
  • global

self;

// Browser
self === window; // true

// Node.js
self === global; // true

How it works?

This project using typeof operator trickly.

typeof operator always return a string. Even with undeclared identifiers, it will return 'undefined' instead of throwing an error.

undeclared; // ReferenceError: undeclared is not defined

typeof undeclared; // 'undefined'

• MDN Docs
• ECMA-262 Spec

• typeof self == 'undefined': Check existing self identifier (should be undefined)
• typeof global == 'object': Check current context is Node.js
• global.self = global: Define self and assign reference of global object

License

MIT