Incorporate a new method into a TypeScript class from a separate file

Question

Incorporate a new method into a TypeScript class from a separate file

I'm curious about the feasibility of adding additional functions to a class prototype in Typescript.

Here's my dilemma: I have a file containing a class, for example image.ts:

export class Image {
    b64img: string;
}

Since this class is generated, I am unable to directly add methods to it. Furthermore, I am utilizing this class in other generated classes, making it impossible to create a new class that extends Image for the purpose of adding functions.

Is there a way for me to include a function in a separate file that can be used on all instances of the Image class?

Thank you

function typescript extension-methods

Answer 1

Answer №1

If you wish to extend a module, it's entirely possible by creating an extension within the same module.

Start by creating a file named image-extension.ts or something similar.

In this file, import the Image as shown below:

import { Image } from `image`;

declare module 'image' {
    export interface Image {
         newMethod: () => void;
    }
}

Image.prototype.newMethod = function() {
    console.log('new method');
}

After importing this file in your project, you can then use the added method like so:

import { Image } from 'image';
import 'image-extension'; // import for side-effects

You may also include the declare module in a d.ts file for automatic loading, and add the actual functions to the prototype in a separate file to ensure they are loaded in your application.

Answer 2

If you wish to extend a module, it's entirely possible by creating an extension within the same module.

Start by creating a file named image-extension.ts or something similar.

In this file, import the Image as shown below:

import { Image } from `image`;

declare module 'image' {
    export interface Image {
         newMethod: () => void;
    }
}

Image.prototype.newMethod = function() {
    console.log('new method');
}

After importing this file in your project, you can then use the added method like so:

import { Image } from 'image';
import 'image-extension'; // import for side-effects

You may also include the declare module in a d.ts file for automatic loading, and add the actual functions to the prototype in a separate file to ensure they are loaded in your application.

Incorporate a new method into a TypeScript class from a separate file

Answer №1

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