feat!: parameter object is null object (#333)

* feat: parameter object is null object

* exclude windows and node 14

Author: Uzlopak

lib/handler-storage.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const { NullObject } = require('./null-object')
 const httpMethodStrategy = require('./strategies/http-method')
 
 class HandlerStorage {
@@ -61,11 +62,20 @@ class HandlerStorage {
   }
 
   _compileCreateParamsObject (params) {
-    const lines = []
+    const fnBody = []
+
+    fnBody.push('const fn = function _createParamsObject (paramsArray) {')
+
+    fnBody.push('const params = new NullObject()')
     for (let i = 0; i < params.length; i++) {
-      lines.push(`'${params[i]}': paramsArray[${i}]`)
+      fnBody.push(`params['${params[i]}'] = paramsArray[${i}]`)
     }
-    return new Function('paramsArray', `return {${lines.join(',')}}`)  // eslint-disable-line
+    fnBody.push('return params')
+    fnBody.push('}')
+
+    fnBody.push('return fn')
+
+    return new Function('NullObject', fnBody.join('\n'))(NullObject)  // eslint-disable-line
   }
 
   _getHandlerMatchingConstraints () {

lib/null-object.js

@@ -0,0 +1,8 @@
+'use strict'
+
+const NullObject = function () {}
+NullObject.prototype = Object.create(null)
+
+module.exports = {
+  NullObject
+}

test/null-object.test.js

@@ -0,0 +1,36 @@
+'use strict'
+
+const { test } = require('tap')
+const { NullObject } = require('../lib/null-object')
+
+test('NullObject', t => {
+  t.plan(2)
+  const nullObject = new NullObject()
+  t.ok(nullObject instanceof NullObject)
+  t.ok(typeof nullObject === 'object')
+})
+
+test('has no methods from generic Object class', t => {
+  function getAllPropertyNames (obj) {
+    var props = []
+
+    do {
+      Object.getOwnPropertyNames(obj).forEach(function (prop) {
+        if (props.indexOf(prop) === -1) {
+          props.push(prop)
+        }
+      })
+    } while (obj = Object.getPrototypeOf(obj)) // eslint-disable-line
+
+    return props
+  }
+  const propertyNames = getAllPropertyNames({})
+  t.plan(propertyNames.length + 1)
+
+  const nullObject = new NullObject()
+
+  for (const propertyName of propertyNames) {
+    t.notOk(propertyName in nullObject, propertyName)
+  }
+  t.equal(getAllPropertyNames(nullObject).length, 0)
+})