functions.js

var codes =
[ 'function funny(p) {\n' +
  '  return [p, s];\n' +
  '}\n',

  'var funny = function (p) {\n' +
  '  return [p, s];\n' +
  '}\n',

  'var funny = function wry(p) {\n' +
  '  return [p, s];\n' +
  '}\n',

  'var funny = new Function("p", "return [p, s];")\n'
]

var template =
  'var s = "GLOBAL";\n' +
  ';(function() {\n' +
    'var s = "LOCAL";\n' +
    'console.log("BEFORE")\n' +
    'console.log("typeof funny = %s", typeof funny)\n' +
    'try {\n' +
    '  console.log("funny.name = %j", funny.name)\n' +
    '} catch (er) {\n' +
    '  console.log("failed reading name")\n' +
    '}\n' +
    'try {\n' +
    '  var res = funny("b")\n' +
    '  console.log("result: %j", res)\n' +
    '} catch (er) {\n' +
    '  console.log("not runnable")\n' +
    '}\n' +
    '{{CODE_RAW}}\n' +
    'console.log("AFTER")\n' +
    'console.log("typeof funny = %s", typeof funny)\n' +
    'try {\n' +
    '  console.log("funny.name = %j", funny.name)\n' +
    '} catch (er) {\n' +
    '  console.log("failed reading name")\n' +
    '}\n' +
    'try {\n' +
    '  var res = funny("a")\n' +
    '  console.log("result: %j", res)\n' +
    '} catch (er) {\n' +
    '  console.log("not runnable")\n' +
    '}\n' +
  '})()\n'


var vm = require('vm')

codes.forEach(function(code) {
  console.log("-------\ncode=%j", code)
  var program = template
    .replace(/\{\{CODE_RAW\}\}/g, code)
  vm.runInNewContext(program, { console: console })
})
console.log("-------")

// $ node functions.js
// -------
// code="function funny(p) {\n  return [p, s];\n}\n"
// BEFORE
// typeof funny = function
// funny.name = "funny"
// result: ["b","LOCAL"]
// AFTER
// typeof funny = function
// funny.name = "funny"
// result: ["a","LOCAL"]
// -------
// code="var funny = function (p) {\n  return [p, s];\n}\n"
// BEFORE
// typeof funny = undefined
// failed reading name
// not runnable
// AFTER
// typeof funny = function
// funny.name = ""
// result: ["a","LOCAL"]
// -------
// code="var funny = function wry(p) {\n  return [p, s];\n}\n"
// BEFORE
// typeof funny = undefined
// failed reading name
// not runnable
// AFTER
// typeof funny = function
// funny.name = "wry"
// result: ["a","LOCAL"]
// -------
// code="var funny = new Function(\"p\", \"return [p, s];\")\n"
// BEFORE
// typeof funny = undefined
// failed reading name
// not runnable
// AFTER
// typeof funny = function
// funny.name = ""
// result: ["a","GLOBAL"]
// -------