import ExpoModulesCore public final class FontLoaderModule: Module { public func definition() -> ModuleDefinition { Name("ExpoFontLoader") Property("customNativeFonts") { return queryCustomNativeFonts() } AsyncFunction("loadAsync") { (fontFamilyAlias: String, localUri: URL) in let fontUrl = localUri as CFURL // If the font was already registered, unregister it first. Otherwise CTFontManagerRegisterFontsForURL // would fail because of a duplicated font name when the app reloads or someone wants to override a font. if FontFamilyAliasManager.familyName(forAlias: fontFamilyAlias) != nil { guard try unregisterFont(url: fontUrl) else { return } } // Register the font try registerFont(fontUrl) // Create a font object from the given URL let font = try loadFont(fromUrl: fontUrl, alias: fontFamilyAlias) if let postScriptName = font.postScriptName as? String { FontFamilyAliasManager.setAlias(fontFamilyAlias, forFont: postScriptName) } } } }