ModuleProxy.ts

type ImportType = ReturnType<typeof require>;

/**
 * Create a lazily-imported module proxy.
 * This is useful for lazily requiring optional dependencies.
 */
const createModuleProxy = <TModule>(getModule: () => ImportType): TModule => {
    const holder: {module: TModule | undefined} = {module: undefined};

    const proxy = new Proxy(holder, {
        get: (target, property) => {
            if (property === '$$typeof') {
                // If inlineRequires is enabled, Metro will look up all imports
                // with the $$typeof operator. In this case, this will throw the
                // `OptionalDependencyNotInstalledError` error because we try to access the module
                // even though we are not using it (Metro does it), so instead we return undefined
                // to bail out of inlineRequires here.
                return undefined;
            }

            if (target.module == null) {
                // lazy initialize module via require()
                // caller needs to make sure the require() call is wrapped in a try/catch
                // eslint-disable-next-line no-param-reassign
                target.module = getModule() as TModule;
            }
            return target.module[property as keyof typeof holder.module];
        },
    });
    return proxy as unknown as TModule;
};

class OptionalDependencyNotInstalledError extends Error {
    constructor(name: string) {
        super(`${name} is not installed!`);
    }
}

export {createModuleProxy, OptionalDependencyNotInstalledError};