Remove keyMirror in PropagationPhases

[vjeux]

See rationale in https://www.facebook.com/groups/2003630259862046/permalink/2097088000516271/

[zpao]

I don't think we can do this one. Because the keys in the object in SimpleEventPlugin use captured as the key (no quotes), then if gcc crushes those keys then React will stop working.

[gaearon]

Good catch, thanks.

[gaearon]

@vjeux

To be specific, the problem is on this line.
GCC will crush lines like these:

{
  abort: {
    phasedRegistrationNames: {
      bubbled: keyOf({onAbort: true}),
      captured: keyOf({onAbortCapture: true}),
    },
  },
}

into

{
  a: {
    b: {
      c: keyOf({e: true}),
      d: keyOf({f: true}),
    },
  },
}

However, phase will be a full string:

var phase = upwards ? 'bubbled' : 'captured';

and so

 var registrationName =
      event.dispatchConfig.phasedRegistrationNames[propagationPhase];            

will give you undefined.

[vjeux]

After asking on twitter, no one has actually successfully used React with GCC Advanced mode itself in a while and all the ClojureScript libraries just use React as is: https://twitter.com/Vjeux/status/770338982110429186

The plan forward is to kill with fire all the abstractions that we have in place that attempts to try to support GCC Advanced mode in order to make the codebase easier to understand.

If we want to support it or some other similar optimizations going forward, we should start a separate effort for it.

[gaearon]

👍