Support empty string as a valid key in a Js.t object

[nireno]

Defining a Js.t object such as let obj = {"": someValue}; throws the following for me:

Fatal error: exception File "lam_methname.ml", line 135, characters 2-8: Assertion failed
File "", line 1:
Error: Error while running external preprocessor

I encountered the problem while trying to define an xstate transient transition which gives special meaning to the empty string key.

Side note: Putting the Js.t example above on the "Try Reason" website currently causes the site to completely crash.

[bobzhang]

how do you access it in this case?

[nireno]

In this use case I don't need to read the value. The object is only used to configure xstate. But I understand the dilemma so if this is too much of an edge you can close this.

If anyone else stumbles on this, a workaround suggested was to use Js.Dict.fromArray:

let states = Js.Dict.fromArray([|
  ("", [|
    {"target": "win", "cond": "didPlayerWin"},
    {"target": "lose", "cond": "didPlayerLose"},
  |]),
|]);

[bobzhang]

We should at least provide a better error message

[bobzhang]

moved to reasonml/reason#2387

[bobzhang]

The work around looks reasonable given this is a corner case

[amiralies]

@bobzhang should we allow this since object access syntax is now x[""] ?