Chapter 11, Implementing Design Patterns – The Functional Way

11.1 Decorating methods, the future way: As we’ve already mentioned, decorators aren’t a fixed, definitive feature at the moment. However, by following tc39.github.io/proposal-decorators/, we can write the following:

const logging = (target, name, descriptor) => {
  const savedMethod = descriptor.value;
  descriptor.value = function (...args) {
    console.log(`entering ${name}: ${args}`);
    try {
      const valueToReturn =
        savedMethod.bind(this)(...args);
      console.log(`exiting ${name}: ${valueToReturn}`);
      return valueToReturn;
    } catch (thrownError) {
      console.log(`exiting ${name}: threw ${thrownError}`);
    ...