svelte/types/runtime/ambient.d.ts

declare module '*.svelte' {
    type Props = Record<string, any>;
    export default class {
        constructor(options: {
            target: Element;
            anchor?: Element;
            props?: Props;
            hydrate?: boolean;
            intro?: boolean;
        });
        $set(props: Props): void;
        $on<T = any>(event: string, callback: (event: CustomEvent<T>) => void): () => void;
        $destroy(): void;
        [accessor: string]: any;
    }
}