Register epub file extension in Obsidian

main.ts

export default class ExamplePlugin extends Plugin {
	async onload() {
		this.registerExtensions(["epub"], "epub");
		this.registerView("epub", (leaf) => new EpubView(leaf));
	}

	onunload() {
	}
}


export class EpubView extends FileView {
	allowNoFile = false;

	private rendition: Rendition;
	private book: Book;

	constructor(leaf: WorkspaceLeaf) {
		super(leaf);
	}

	getViewType(): string {
		return "epub";
	}

	onunload(): void {
		this.contentEl.empty();
	}

	canAcceptExtension(extension: string) {
		return "epub" === extension;
	}

	onload() {
		super.onload();
	}

	async onLoadFile(file: TFile): Promise<void> {
		this.contentEl.setAttr('id', 'area');
		const content = await this.app.vault.adapter.readBinary(file.path);

		this.book = ePub(content);
		this.rendition = this.book.renderTo("area", {width: 600, height: 400});
		await this.rendition.display();

		return super.onLoadFile(file);
	}

	onUnloadFile(file: TFile): Promise<void> {
		this.rendition.destroy();
		this.book.destroy();
		this.contentEl.empty();

		return super.onUnloadFile(file);
	}
}