Typescript namespaces support

[pushkine]

Hey I absolutely adore sucrase, thank you so much for building it!~

It's been mentioned before on #465 and #641, sucrase doesn't handle namespaces

I love namespaces and use them a lot, they're basically glorified objects and their output is very similar to enums.

I'd love to see them supported in sucrase, otherwise I think the readme really should mention that they're stripped from the output. Note that in runtime it shows up as "cannot access x in undefined" which is usually a sign of cyclical dependency

Input

export namespace foo {
	export function bar() {}
}
foo.bar();

Typescript output

export var foo;
(function (foo) {
    function bar() { }
    foo.bar = bar;
})(foo || (foo = {}));
foo.bar();

Sucrase output

"use strict";


foo.bar();