How to supplement your Typescript type definitions

A collection of different typescript definitions to supplement non-typescript libraries.

Extending existing library definitions

To extend a class definition of an npm module you can use the following syntax in your .d.ts file

declare module '@ionic/angular' {
    export interface Slides {
        update(): void;
        slideTo(index: number, delay: number): void;
    }
}

Declaring Variables in the global scope or on window

declare global {
    interface Window {
        VAR_NAME: any;
    }
    let ga: (...args) => {};
}