eslint-plugin-encapsulate

Generate errors for using private method outside the class.

Installation

You'll first need to install ESLint:

$ npm i eslint --save-dev

Next, install eslint-plugin-encapsulate:

$ npm install eslint-plugin-encapsulate --save-dev

Usage

Add encapsulate to the plugins section of your .eslintrc configuration file. You can omit the eslint-plugin- prefix:

{
  "plugins": [
    ...,
    "encapsulate", 
  ],
  "extends": [
    ...
  ],
  "overrides": [
      {
        ....,
        "rules": {
          "encapsulate/private-method": "error",
        },
      },
  ],
  ...
}

Example:

class SportCar {
  protected name: string;
  protected speed: number;

  constructor(name: string) {
    this.name = name;
  }

  _enableTurbo(extraSpeed: number): void {
    this.speed += extraSpeed;
  }

  increaseSpeed(): void {
    this.speed = 50;
  }
}

class Ferrari extends SportCar {
  increaseSpeed(): void {
    this.speed = 50;
    this._enableTurbo(50);
  }
}

const main = () => {
  const enzo = new Ferrari('Enzo');
  enzo.increaseSpeed();
  enzo._enableTurbo(50);  // Error: Private method is inaccessible from outside

  const daytona = new Ferrari('Daytona');
  daytona.increaseSpeed();
  // eslint-disable-next-line encapsulate/private-method
  daytona._enableTurbo(40); // ok
};