Method once

frontend/public/tinymce/tinymce.d.ts:2614–2614

(name: K, callback: (event: EditorEvent<MappedEvent<T, K>>) => void)

    on<K extends string>(name: K, callback: (event: EditorEvent<MappedEvent<T, K>>) => void, prepend?: boolean): EventDispatcher<T>;
    off<K extends string>(name?: K, callback?: (event: EditorEvent<MappedEvent<T, K>>) => void): EventDispatcher<T>;
    once<K extends string>(name: K, callback: (event: EditorEvent<MappedEvent<T, K>>) => void): EventDispatcher<T>;
    hasEventListeners(name: string): boolean;
}
interface URISettings {