Node.JS vm's global sandbox bug (although they call it feature)...

extension.js

// Let's extend prototype of Object with something like delete in ruby, but
// we'll call it grab (just to avoid keyword name collision)
Object.prototype.grab = function grab(key) {
  var val = this[key];
  delete(this[key]);
  return val;
};

output.log

test.js, Object.prototype.grab: function
test.js, {}.grab: function
test.js, outter.grab: function
---
script-1.js, Object.prototype.grab: undefined
script-1.js, {}.grab: undefined
script-1.js, outter.grab: function
script-2.js, Object.prototype.grab: undefined
script-2.js, {}.grab: undefined
script-2.js, outter.grab: function
---
script-1.js, Object.prototype.grab: function
script-1.js, {}.grab: undefined
script-1.js, outter.grab: function
script-2.js, Object.prototype.grab: function
script-2.js, {}.grab: undefined
script-2.js, outter.grab: function
---
script-1.js, Object.prototype.grab: function
script-1.js, {}.grab: undefined
script-1.js, outter.grab: function
script-2.js, Object.prototype.grab: function
script-2.js, {}.grab: undefined
script-2.js, outter.grab: function

script-1.js

console.log('script-1.js, Object.prototype.grab: ' + typeof Object.prototype.grab);
console.log('script-1.js, {}.grab: ' + typeof {}.grab);
console.log('script-1.js, outter.grab: ' + typeof outter.grab);

script-2.js

// this is predictably works exatly as script-1, just because require is in the
// different fork (i guess), so calling require here calls it in fact in scope
// of main script, but not here.
require('./extension.js');

console.log('script-2.js, Object.prototype.grab: ' + typeof Object.prototype.grab);
console.log('script-2.js, {}.grab: ' + typeof {}.grab);
console.log('script-2.js, outter.grab: ' + typeof outter.grab);

test.js

var fs  = require('fs'),
    vm  = require('vm');


// require our extensions
require('./extension.js');


// our humble Object instance
var outter = {};


// sandbox for the runner
var sandbox = {require: require, console: console, outter: outter};


function RunForestRun(filename) {
  var content = fs.readFileSync(filename, 'utf8');
  vm.runInNewContext(content, sandbox);
}


function RunLolaRun(filename) {
  var content = fs.readFileSync(filename, 'utf8');
  vm.runInNewContext(content, sandbox);
}


// check what we have here to be sure our object was extended
console.log('test.js, Object.prototype.grab: ' + typeof Object.prototype.grab);
console.log('test.js, {}.grab: ' + typeof {}.grab);
console.log('test.js, outter.grab: ' + typeof outter.grab);


// ready, steady, go, i feel dumb
console.log('---');
RunForestRun('./script-1.js');
RunForestRun('./script-2.js');


// and now, the most interesting thing: we can expose our extended object,
// so it will have correct prototype inside script files, BUT, instances will
// not be created with that prototype
sandbox.Object = Object;
console.log('---');
RunForestRun('./script-1.js');
RunForestRun('./script-2.js');


console.log('---');
RunLolaRun('./script-1.js');
RunLolaRun('./script-2.js');

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