protect-class v0.2.1

Protect class js

Creates a protected proxy class that restricts access to certain properties and allows viewing only of the class's public fields, including getters.

Install

npm install protect-class

Usage

Javascript

import { protect } from 'protect-class';

class Foo {
  bar = 'bar';
}

const cls = protect(new Foo());
...

Typescript

import { Protect, protect } from 'protect-class';

@Protect()
class Foo {
  public bar: string = 'bar';
}

const cls = new Foo();
/*
  OR
  const cls = protect(new Foo());
*/
...

Examples

Demonstration of the utility. In the following example, we will create a custom class:

class Test {
  test1;
  test2 = {
    test4: undefined
  };
  #test3;
  
  get test3() {
      return this.#test3;
  }
  
  set test3(value) {
      this.#test3 = value;
  }
}

Let's see how an instance of the class behaves without protection:

const cls = new Test();

console.log(Object.keys(cls));
// [ 'test1', 'test2' ]

console.log({...cls}); 
// { test1: undefined, test2: { test4: undefined } }

console.log({...Object.assign(cls, { test1: 'test1', test3: 'test3', test5: 'Hello' })}); 
// { test1: 'test1', test2: { test4: undefined }, test5: 'Hello' }

console.log(cls.test5); 
// Hello

console.log(JSON.stringify(cls)) 
// {"test1":"test1","test2":{},"test5":"Hello"}

As a result, we do not have the test3 field in the output, but a new test5 field has appeared :confused:

And with protection:

const protect_cls = protect(new Test());

console.log(Object.keys(protect_cls));
// [ 'test1', 'test2', 'test3' ]

console.log({...protect_cls});
// { test1: undefined, test2: { test4: undefined }, test3: undefined }

console.log({...Object.assign(protect_cls, { test1: 'test1', test3: 'test3', test5: 'Hello' })});
// { test1: 'test1', test2: { test4: undefined }, test3: 'test3' }

console.log(protect_cls.test5);
// undefined

console.log(JSON.stringify(protect_cls))
// {"test1":"test1","test2":{},"test3":"test3"}

The protected instance outputs the getter key test3 and when executing Object.assign did not add the new field test5 :sunglasses:

Options

protect(cls: Object, options?: IOptionsProtectedObject)

Creates a protected class proxy that restricts access to certain properties.

const cls = protect(new Foo(), {
  allowProtectedField: true,
  allowReadError: true,
  allowWriteError: true,
  disableDeleteError: true,
  disableCache: true
});

Protect(options?: IOptionsProtectedObject)

Decorator function that creates a protected class proxy.

@Protect({
  allowProtectedField: true,
  allowReadError: true,
  allowWriteError: true,
  disableDeleteError: true,
  disableCache: true
})
class Foo {
  public bar: string = 'bar';
}

options: IOptionsProtectedObject

• allowProtectedField: boolean - (default: false) Allow access to protected fields (fields starting with "_").
• allowReadError: boolean - (default: false) Allow throwing an error when trying to access an unknown property.
• allowWriteError: boolean - (default: false) Allow throwing an error when trying to write to an unknown property.
• disableDeleteError: boolean - (default: false) Disable throwing an error when trying to delete a property.
• disableCache: boolean - (default: false) Disable caching of the enumerable getters.