context.js

const hasHandler = { has }
const allHandlers = { has, get }
const globals = new Set()
let temp

let globalObj
if (typeof window !== 'undefined') globalObj = window // eslint-disable-line
else if (typeof global !== 'undefined') globalObj = global // eslint-disable-line
else if (typeof self !== 'undefined') globalObj = self // eslint-disable-line
globalObj.$nxCompileToSandbox = toSandbox
globalObj.$nxClearSandbox = clearSandbox

export function expose (...globalNames) {
  for (let globalName of globalNames) {
    globals.add(globalName)
  }
}

export function hide (...globalNames) {
  for (let globalName of globalNames) {
    globals.delete(globalName)
  }
}

export function hideAll () {
  globals.clear()
}

function has (target, key) {
  return globals.has(key) ? (key in target) : true
}

function get (target, key) {
  return key in temp ? temp[key] : target[key]
}

function toSandbox (obj, tempVars) {
  if (tempVars) {
    temp = tempVars
    return new Proxy(obj, allHandlers)
  }
  return new Proxy(obj, hasHandler)
}

function clearSandbox () {
  temp = undefined
}