ExampleDecorator.ts

import PublicError from './PublicError';

// Based catch-decorator by Enkot https://github.com/enkot/catch-decorator

// decorator factory function
export default (name: string, message?: string): any => {
    return (
        target: any,
        propertyKey: string,
        descriptor: PropertyDescriptor,
    ) => {
        // save a reference to the original method
        const originalMethod = descriptor.value

        // rewrite original method with custom wrapper
        descriptor.value = function (...args: any[]) {
            try {
                const result = originalMethod.apply(this, args)

                // check if method is asynchronous
                if (result && typeof result.then === 'function' && typeof result.catch === 'function') {
                    // return promise
                    return result.catch((error: any) => {
                        // TODO
                        if (error instanceof PublicError)
                            throw error;
                        throw new PublicError(error, name, message);
                    })
                }

                // return actual result
                return result
            } catch (error) {
                throw new PublicError(error, name, message);
            }
        }

        return descriptor
    }
}