ES6 Realms API

realms-api.md

Notational Conventions

This section describes the conventions used here to describe type signatures.

A [T] is an array-like value (only ever used read-only in this API), i.e., one with an integer length and whose indexed properties from 0 to length - 1 are of type T.

A type T? should be read as T | undefined -- that is, an optional value that may be undefined.

Realms

A realm object abstracts the notion of a distinct global environment.

Extensible web: This is the dynamic equivalent of a same-origin <iframe> without DOM.

Realm Constructor

r = new Realm(options,      // {
                            //   eval: {
                            //     direct: {
                            //       translate: ((string) -> string)?,
                            //       fallback: ((any, ...any) -> any)?
                            //.    }?,
                            //     indirect: ((string) -> any)?
                            //   }?,
                            //   Function: ((string, string, ("function" | "function*")) -> function)?
                            // }?
              initializer); // ((object) -> any)?

Every component of the constructor argument is optional (meaning that it can be undefined and will be provided with a default behavior).

The initializer object is passed an object containing the standard ECMAScript builtins for a global object. A host environment may also provide additional builtins specific to the host environment. (For example, the browser would provide atob and btoa and other standard browser globals that are not tied to the DOM.) The this binding of the initializer function is provided as the new realm object. This can be used to initialize the realm, for example:

var realm = new Realm(options, function(builtins) {
    Object.mixin(this.global, builtins);
});

Realm Properties

global

The global object associated with the realm.

Realm Methods

eval

Synchronously execute a top-level script.

Extensible web: This is the dynamic equivalent of a <script> in HTML.

// eval : (string) -> any
v = r.eval(src)

Loaders

This section describes how the Loader class is extended to integrate with custom realms.

Loader Constructor

l = new Loader({
  realm,      // Realm?
  ...
}) // : Loader<ModuleAddress, ModuleSource>

Loader Properties

realm

Returns the realm associated with the loader.

global

Convenience: returns the global associated with the loader's realm.

Is this proposal alive?

This is the dynamic equivalent of a same-origin <iframe> without DOM.

Is there access to the same DOM as in the main global scope? Or just no DOM at all like a Web Worker?

https://github.com/FUDCo/proposal-frozen-realms is inherited of this.

yeah, we are actually moving to https://github.com/caridy/proposal-realms, where https://github.com/FUDCo/proposal-frozen-realms is a related (dependent of realms) effort, we will be working on both at the same time :)

Does https://github.com/caridy/proposal-realms subsume this proposal? Can we just consider that one to be the latest?

@erights, yes, https://github.com/caridy/proposal-realms subsume this proposal.