Question

How can I control the value of the top-level this variable when running a script with the vm module?

As far as I can tell:

• With vm.runScriptIn(New)Context(…), the value of this is always {}.
• With vm.runScriptInThisContext(…), the value of this is always GLOBAL.

Is it possible to control that value any further?

Edit: For example, just in case you don’t trust me:

$ cat x.js
var vm = require("vm");
vm.runInNewContext("console.log('this:', this)", { foo: 42, console: console }));
$ node x.js
this: {}

Edit 2: In fact, it looks like this is set to the context, console.log just lies:

$ cat x2.js
var vm = require("vm");
vm.runInNewContext([
    "console.log('this:', this)",
    "for (var key in this) console.log('this has key:', key);",
    "console.log('this.foo:', this.foo);"
].join("\n"), { foo: 42, console: console }));
$ node x2.js
this: {}
this has key: foo
this has key: console
this has key: key
this.foo: 42

Answer 1

As per the documentation for vm module..

//this.hi in the vm becomes 'hello'
vm.runInNewContext(stuff, { hi: 'hello' });