JavaScript: casting with "checkJs": true

[bruce965]

I opened a question on StackOverflow and got no answers, so I guess this is still a missing feature.

I'm looking for a way to do a cast with JavaScript Language Service code-checker enabled.

TypeScript Version: 2.4.1 / 2.5.0-dev.20170629

// JavaScript

const something = window.something;

// TypeScript equivalent

const something: SomethingConstructor = (window as any).something;

// JavaScript with checkJs

const anyWindow = (/** @type {any} */(window));  // Property 'something' does not exist on type 'Window'.
const something = (/** @type {SomethingConstructor} */(anyWindow.something));

// Workaround for this specific situation

/** @type {any} */
const anyWindow = window;
/** @type {SomethingConstructor} */
const something = anyWindow.something;

---

References:

#9694

[rbuckton]

This is a duplicate of #5158.