Convert to destructed refactoring not enabled in JavaScript?

[mjbvz]

TypeScript Version: 3.5.0-dev.20190404

Search Terms:

• refactor / refactoring
• convert to destructed parameters

Code
For a simple js file

function doStuff(a, b, c) {
    return a + b + c;
}

doStuff('a', 'b', 1);
doStuff('x', 'y', 2);

Expected behavior:
A convert to restructured refactoring is available on doStuff

Actual behavior:
I'm not seeing any such refactoring show up in js files

Playground Link:

Related Issues:

• Refactoring to convert to "named parameters" #23552

[DanielRosenwasser]

In #29694 and #30089, we decided that due to the lack of type information, JS refactorings were disabled if the declarations were untyped. For some motivation, I've had the chance of speaking with developers who had aversions to any refactorings in which a failed refactor couldn't be caught by the type checker. The hazards are worse in JS code which is untyped.

This is weird, since the same limitation isn't present for the same TypeScript code (which is also fully untyped in the parameters list.

We also don't surface the refactoring for JSDoc'd code either.

@sandersn