Alternative Methods for Setting New Properties on window in TypeScript

Direct Assignment:

• The most straightforward method is to directly assign a value to the new property:

window.myNewProperty = "Hello, world!";

This approach creates a new property named myNewProperty on the window object and assigns the string "Hello, world!" to it.

Using declare Keyword:

• For more explicit type declarations, you can use the declare keyword:

declare global {
  interface Window {
    myNewProperty: string;
  }
}

window.myNewProperty = "Hello, world!";

This approach defines a global interface named Window and adds a new property myNewProperty of type string to it. Then, you can assign a value to this property using the window object.

Key Points:

• Ensure that the window object is available in your TypeScript environment. This is typically the case in web browsers.
• Choose the method that best suits your needs based on the level of type safety and explicitness you desire.
• Be aware that modifying the window object can potentially affect the behavior of your application and other scripts running in the same environment. Use this technique carefully and consider the potential side effects.

Setting a New Property on window in TypeScript

window.myNewProperty = "Hello, world!";

This provides more explicit type declarations:

declare global {
  interface Window {
    myNewProperty: string;
  }
}

window.myNewProperty = "Hello, world!";

Example: Creating a Global Utility Function

Here's an example of creating a global utility function:

declare global {
  interface Window {
    myUtilityFunction: (message: string) => void;
  }
}

window.myUtilityFunction = (message: string) => {
  console.log(message);
};

Now you can use this function anywhere in your code:

window.myUtilityFunction("This is a message from my utility function!");

Key points to remember:

• Type safety: Using the declare keyword ensures type safety for the new property.
• Global access: The property becomes accessible from anywhere in your code.
• Side effects: Be cautious when modifying the window object, as it can affect other scripts.

Alternative Methods for Setting New Properties on window in TypeScript

While the direct assignment and declare keyword methods are commonly used, there are a few alternative approaches you can consider:

Using an Extension Interface:

• Create a new interface that extends the Window interface.
• Add the desired property to the new interface.
• Use the extended interface to type the window object.

interface MyWindow extends Window {
  myNewProperty: string;
}

declare var window: MyWindow;

window.myNewProperty = "Hello, world!";

Using a Global Variable:

• Declare a global variable with the desired property type.
• Assign the window object to the global variable.
• Access the property through the global variable.

declare var globalWindow: Window;

globalWindow = window;

globalWindow.myNewProperty = "Hello, world!";

Using a Singleton Pattern:

• Create a singleton class that holds the window object.

class WindowSingleton {
  private static instance: WindowSingleton;

  private window: Window;

  private constructor() {
    this.window = window;
  }

  public static getInstance(): WindowSingleton {
    if (!WindowSingleton.instance) {
      WindowSingleton.instance = new WindowSingleton();
    }
    return WindowSingleton.instance;
  }

  public get myNewProperty(): string {
    return this.window.myNewProperty;
  }

  public set myNewProperty(value: string) {
    this.window.myNewProperty = value;
  }
}

const windowSingleton = WindowSingleton.getInstance();
windowSingleton.myNewProperty = "Hello, world!";

Choosing the Best Method:

• Direct assignment: Simple and straightforward for basic cases.
• declare keyword: Provides explicit type declarations and is often preferred for global properties.
• Extension interface: Useful for creating custom window interfaces and maintaining type safety.
• Global variable: Can be used for more complex scenarios where you need to control access to the window object.
• Singleton pattern: Ensures a single instance of the window object and provides a controlled way to access its properties.