proxy.js

// @ts-nocheck
import vm from 'vm'
import _debug from 'debug'
const debug = _debug('wf:enhancer')


class WObject {
  constructor(source: any) {
    this._w = source
    return new Proxy(this, {
      get(target, property) {
        debug('Property %s', property)
        debug('Target: %o', target)
        if (typeof Reflect.get(target, property) === 'function') {
          return (...args) => {
            debug('in proxy %o', args)
            return Reflect.get(target, property).apply(target, args)
          }
        }
        if (Reflect.has(target._w), property) {
          const value = Reflect.get(target._w, property)
          switch (true) {
            case Array.isArray(value): {
              return new WArray(value)
            }
            default:
              return new WObject(value)
          }
        } else {
          throw new Error(`Undefined property: ${property}`)
        }
      }
    })
  }

  eeq(v: any): boolean {
    debug('eeq called: %s', v)
    debug('valueOf: %s', this._w)
    return this._w === v
  }
}


class WArray extends WObject {
  size(): numeber {
    debug('Array size:', this._w)
    return new WObject(this._w.length)
  }
}

const params = new WObject({ test: { cool: { foo: [1,2,[9,8,7,6],4] } } });

const ctx = vm.createContext({ console, params })

vm.runInContext('console.log(params); if (params.test.cool.foo[2].filter(v => (v > 7)).size().eeq(4)) { console.log("test") }', ctx)

$ DEBUG=wf:* ts-node src/enhancer.ts
WObject { _w: { test: { cool: [Object] } } }
WObject { _w: { test: { cool: [Object] } } }
wf:enhancer Property test +0ms
wf:enhancer Target: WObject { _w: { test: { cool: [Object] } } } +0ms
wf:enhancer Property cool +0ms
wf:enhancer Target: WObject { _w: { cool: { foo: 4 } } } +0ms
wf:enhancer Property foo +0ms
wf:enhancer Target: WObject { _w: { foo: 4 } } +0ms
wf:enhancer Property eeq +1ms
wf:enhancer Target: WObject { _w: 4 } +0ms
wf:enhancer in proxy [ 4 ] +0ms
wf:enhancer eeq called: 4 +0ms
wf:enhancer valueOf: 4 +0ms
test