[isntitvacant]

(I assume) the reason that node chose to go with a single global object (which is optional[0]) is that JS gets a bit hinky when dealing with multiple contexts: e.g., an array returned from a function defined in a different context will not satisfy `[] instanceof Array`, since the receiving module's instance of `Array` is not strictly equal to to called module's copy of `Array`.

In practice, this problem is why you see `Array.isArray`, `jQuery.isArray`, `_.isArray` and friends so often -- they exist to give a canonical, non-"check if any member of X's inheritance chain matches Y.prototype" way to determine if a given instance is actually an array.

So, in summation: yes, it's weird that Node has this, but ultimately it's a lesser-vilified problem of JavaScript's.

[0]: https://github.com/joyent/node/blob/master/lib/module.js#L51 -- `NODE_MODULE_CONTEXTS=1 node <file.js>` will run separate modules in separate global contexts.

[bzbarsky]

Thanks for the pointer to NODE_MODULE_CONTEXTS!