Replace function constructor with defineProperty to preserve arity without eval [#41]

Author: davidje13

index.js

@@ -64,20 +64,6 @@ function convertDataDescriptorToAccessor (obj, prop, message) {
   return descriptor
 }
 
-/**
- * Create arguments string to keep arity.
- */
-
-function createArgumentsString (arity) {
-  var str = ''
-
-  for (var i = 0; i < arity; i++) {
-    str += ', arg' + i
-  }
-
-  return str.substr(2)
-}
-
 /**
  * Create stack string from stack.
  */
@@ -415,20 +401,17 @@ function wrapfunction (fn, message) {
     throw new TypeError('argument fn must be a function')
   }
 
-  var args = createArgumentsString(fn.length)
+  var deprecate = this
   var stack = getStack()
   var site = callSiteLocation(stack[1])
 
   site.name = fn.name
 
-  // eslint-disable-next-line no-new-func
-  var deprecatedfn = new Function('fn', 'log', 'deprecate', 'message', 'site',
-    '"use strict"\n' +
-    'return function (' + args + ') {' +
-    'log.call(deprecate, message, site)\n' +
-    'return fn.apply(this, arguments)\n' +
-    '}')(fn, log, this, message, site)
-
+  function deprecatedfn () {
+    log.call(deprecate, message, site)
+    return fn.apply(this, arguments)
+  }
+  Object.defineProperty(deprecatedfn, 'length', { value: fn.length })
   return deprecatedfn
 }