TypeScript - Decorators

https://www.typescriptlang.org/docs/handbook/decorators.html

tsconfig.json

{
  "compilerOptions": {
    "target": "ES5",
    "experimentalDecorators": true
  }
}

https://github.com/dream-coding-academy/typescript_motion/blob/master/src/decorators/log.ts

function Log(_: any, name: string, descriptor: PropertyDescriptor): PropertyDescriptor {
  const newDescriptor = {
    ...descriptor,
    value: function (...args: any[]): any {
      console.log(`Calling ${name} with arguments:`);
      console.dir(args);
      const result = descriptor.value.apply(this, args);
      console.log(`Result:`);
      console.dir(result);
      return result;
    },
  };

  return newDescriptor;
}

class Calculator {
  @Log
  add(x: number, y: number): number {
    return x + y;
  }
}

const calculator = new Calculator();
console.log(calculator.add(1, 2));