traceJS.js

function traceMethodCalls(obj) {
  const handler = {
    get(target, propKey, receiver) {
      console.log('GET', propKey);
      const targetValue = target[propKey]; // Reflect.get(target, propKey, receiver);
      if (typeof targetValue === 'function') {
        return function(...args) {
          console.log('CALL', propKey, args);
          return targetValue.apply(target, args); // (A)
        }
      }
      return targetValue;
    },
    set(obj, prop, value) {

      // The default behavior to store the value
      obj[prop] = value;
      console.log('SET', prop, value);
      // Indicate success
      return true;
    }
  };
  return new Proxy(obj, handler);
}