Flow: Problem with Proxy objects

[fgarcia]

I am trying to add Flow types to this code example, where a Proxy sets a default for the first argument of a function

let panda = {
  fn: function(n: number, s: string) {
    console.log(n, s);
  }
}

let handler = {
  get: function(target,name) {
    return (s) => target[name](1, s)
  }
}

let g = new Proxy(panda, handler)
g.fn('k')

Here Flow complains forcing me to type invalid code.

// WRONG, but it is what Flow wants
// g.fn(2, 'k')

How can I get Flow to properly identify my Proxy?

This is the error I get with the good version:

 19: g.fn('k')
     ^^^^^^^^^ call of method `fn`
 19: g.fn('k')
          ^^^ string. This type is incompatible with
  4:   fn: function(n: number, s: string) {
                       ^^^^^^ number

[calebmer]

Closing since we currently planning on adding support for proxies.

[fgarcia]

@calebmer Which issue should I follow to track this feature and find out when it will be released?

[gajus]

Can this be re-opened if these is no other issue to track?

[bugs181]

Still no progress after almost 4 years? Just ran into this issue. Unless I'm doing something blatantly wrong? New to type systems and it hasn't been as easy as the whitepapers make it seem.

Code example:

constructor(): Proxy<FlowInterface> {}

Error:

Cannot return `new Proxy(...)` because  `FlowInterface` [1] is incompatible with  `Proxy` [2].Flow(incompatible-return)

Changing to this fixes the problem:

constructor(): Proxy<any> {}