JavaScript Magic Functions

example.js

'use strict'

const magic = require('./magic')

class Request {
  constructor(req) {
    this.req = req
    this.user = 'morrelinko'
  }
  
  __get (prop) {
    return this.req[prop]
  }
  
  __set (prop, value) {
    this.req[prop] = value
  }
}

magic.js

'use strict'

const assert = require('assert')

module.exports = function (obj) {
  return new Proxy(obj, {
    get (target, prop, receiver) {
      if (prop in target) {
        return Reflect.get(target, prop, receiver)
      }

      if (target.__get) {
        return target.__get(prop)
      }
    },

    set (target, prop, value, receiver) {
      if (prop in target) {
        return Reflect.set(target, prop, value, receiver)
      }

      if (target.hasOwnProperty('__set')) {
        target.__set(prop)
      }

      return true
    }
  })
}