ES6 and Object.defineProperties issue

lets say i have the following class:

class Object3D extends EventDispatcher {

	constructor() {

		super();

		const quaternion = new Quaternion();

		Object.defineProperties( this, {
			quaternion: {
				configurable: true,
				enumerable: true,
				value: quaternion
			}
		} );
      }

       onRotationChange() {
		this.quaternion.setFromEuler(........);
	 }
 }

and the following warning:

core/Object3D.js:123:7: WARNING - [JSC_INEXISTENT_PROPERTY] Property quaternion never defined on Object3D
  123| 		this.quaternion.setFromEuler();
       		   ^^^^^^^^^^

I have no idea what i do wrong, maybe i missed something ?

[nreid260]

Just want to add, the compiler recognizes properties creates by Object.defineProperties during optimizations, but not during typechecking. As such, we believe things are working as intended.

That distinction might feel arbitrary, but optimizations generally require less information about properties (usually just “does this name exist somewhere in the program?”) so it’s easier to add support. Recognizing them during typechecking is more nuanced.

Additionally, optimization failure can cause runtime behaviour issues, so we need to be very conservative, and often silently cancel optimizations when something might be wrong. In contrast, typechecking failure is a compile-time problem, so we can make it more user visible, and defer to the user (via suppressions or annotations) when we get false positives.

[treblereel]

@ctjlewis thanks for your clarification, so it means closure ignores Object.defineProperties/Object.defineProperty ? Ok, i am working on three.js and i didn’t want to change the code too much but looks like i have no choice to make it closure compatible.