My rough understanding is that Caja for JavaScript kind of did that. Libraries didn't have access to the whole scope, could only access what they were given via

My rough understanding is that Caja for JavaScript kind of did that. Libraries didn't have access to the whole scope, could only access what they were given via capabilities. https://en.wikipedia.org/wiki/Caja_project https://en.wikipedia.org/wiki/Caja_project